Need to get this off my chest

I'm sorry in advance as this is kinda long.

I had just recently got into a relationship and my boyfriend knew that I have a few issues, some he knew about and some he didn't but he didn't mind. 

The day before we were due to fly out I was finishing off my packing and talking to my mums partner about university, as I am currently studying A-Levels. As I was talking I noticed that he was watching me oddly and it was starting to make me uncomfortable as he was leaning in the doorway to my room and looked as though he was going to cry but was smiling all the time. 

I asked him what was wrong as I didn't know what was causing him to act strangely towards me all of a sudden. He didn't say anything at first then said it was nothing and walked away. I was really confused as he was acting completely out of character, I asked again and he came back and began to tell me that he loved me and that he wished he could have me all to himself and keep me away from everyone. 

I have known him for as long as I can remember and he has always been part of my life, so I thought that he was saying those things as a father might because he is normally very reserved with his feelings so I thought that talking about university had made him realise that I'm growing up and that pretty soon I'm not going to be at home and that he won't be able to look after me. 

I laughed and went to give him a hug, he hugged me back but then gave his words a whole different meaning as he moved to kiss me.

I pushed him away from me and in utter shock sat back on my bed facing one wall, watching from the corner of my eye to see what he was doing. 

At first he didn't move, he just stood there and then came to my bed and sat on the floor and tried to hold my hand, I moved further away from him but he kept a hand on my knee as he began to apologise over and over as he knew what he had done was wrong. 

I couldn't move, I wanted to shout and scream and cry and mostly I wanted to run away but I couldn't, all I could do was sit there and stare at the wall. He kept apologising and I couldn't take it so I just kept repeating its ok its ok, over and over again more to myself than to him but he responded and said that it wasn't ok and that he shouldn't have said anything.

He stood up and noticed that my mum had just got back from the shops with my little brother and he went straight out of my room, and told me not to say anything and again that he was sorry.

I still didn't move, I heard my mum get in and then heard them talking before I heard him leave. 

My brother came into my room but I didn't hear what head said so he nudged me and I didn't respond so he left and then a began to silent cry and shake uncontrollably. 

My boyfriend was playing cricket at the time so I called a friend and I couldn't speak I was just crying so she said she'd meet me near my house.

I couldn't look at my mum so I ran out of the house after quickly managing to shout that I was meeting a friend and wouldn't be long. I ran away from my house faster than I ever have in my life. I met my friend and we went to watch my boyfriend play cricket so I could calm down.

My friends and my boyfriend tried to talk me out of going on the two week holiday the next day but they didn't succeed. So I went. 

I was terrified the whole time in case he tried something again and as well I was shut off from everyone as we only had 100 texts between us to stay in touch with family only. 

Half way into the holiday my brother got ill and my mum stayed in the room to look after him and made me go with her partner to get breakfast. I was shaking the whole time and he hadn't spoken a single word to me since the day we left, but then he asked me if I was ok and then told me to forget about what happened and go on like it never happened, I told him that it was not a thing that I could easily forget, and that I didn't want him to talk to me or come near me again. 

So he didn't, but I was still terrified. 

When we got home I found myself putting piles of stuff behind my door so it couldn't be opened and crying myself to sleep every night for weeks.

My boyfriend and my friends at sixth form became increasingly concerned as I had started to go back to an old coping method, self harm. They were begging me to tell a member of staff at school or my mum, in the end about 4 weeks after that day and after an argument with a friend i ran to the office and told them everything, I sat there in tears and was told I couldn't go home, I couldn't see anyone and that I couldn't talk to anyone which meant I had to stay off my phone. They called my mum at work after the members of staff at school in charge of safe guarding had interviewed me. I had to sit in a room on my own for hours, at the end of the school day I was still there as my mum couldn't come in until after work at 5. My time alone was broken briefly when they allowed my boyfriend to come in to calm me down, he didn't ask any questions, he just held me and told me that he was proud I had finally told someone and that I would be OK. 

When my mum finally arrived she still had no idea at all what had happened or why I was being kept at school. I couldn't bring myself to tell her so a staff me never did it for me, while I was in a separate room. She came to fetch me after she told my mum. My mum was devastated. She couldn't stop crying. After an hour more sat talking about it again, I was finally allowed to go to somewhere safe. For me that's my dads. He didn't know what had happened at all. He was out when we got there, so we let ourselves in and waited for him to come home. 

On our way to my dads my mum had picked up my little brother from the house although her partner was home by then so we waited in the car at the top of the street for my brother to come out and get in the car before leaving again. 

When my dad got home I told him what had happened and he checked I was ok but didn't say anything else. 

Since that day, which was early September, my contact with my mum has disappeared as I am still living at my dads, I have been back to talk to her partner about what happened and he again apologised but said that he meant no harm. My mum hasn't asked him to leave as he has no where else to go and she has put it behind her now and all but forgotten about it. 

I had to have counselling for months but I have stopped going due to lack of time with revision for upcoming exams. 

My boyfriend is still my constant support but now I am finding that I've retracted myself from my friends and more from my family. I don't see my mum for weeks at a time and I don't talk to her at all some weeks. 

I've started to self harm again and I'm starting to lose myself.

He is still with my mum and still lives in the house. 

I miss my mum and she wants me to go back home.

Can anyone offer any advice on what I should do because I really don't know what I should do anymore 😢 

And I'm sorry this is stupidly long, I've not told anyone outside my close friends and most my family don't know.