Post natal depression?

Hey so first of all I just wanna say I’m a young mother, I’m 18 years old and became a single mother when my son was 3 months old. I was in a very controlling and abusive, manipulative relationship. I was there for a year and a half and it involved drugs and moving in with him, sex all of the time (if I didn’t do it I wasn’t interested in him, he deserved it) etc. I don’t wanna go to much into it as it really really messes with my head but I wasn’t allowed to speak to people or my parents (he said they weren’t good for me, this comes in later though) anyway after I had my son I wasn’t allowed out unless he was there really and even in the hospital stay (I was there a week by myself because guys can’t be on the Womens ward from evening till afternoon) he got mad at me for FaceTiming one of my friends and not telling him. Even though when I was in active labour I had to give him a BJ on the hospital bed and he wouldn’t leave me alone until I did?! Anyway whenever I left the house it had to be with him or he would be on the phone with me and the only reason he wouldn’t come was because he couldn’t be bothered. He used the excuse we couldn’t go out because of corona but this is before even the first lockdown and it was just in wuhan in China. Any excuse not to actually lift a finger. People round town didn’t like him because of the drugs and things he was involved in. Anyway one day we had an argument after me having no sleep and him sleeping upstairs I took my son out in his pram and that was me apparently going to meet a boy?! He did this everytime and we argued at least 5-6 times everyday but it was just the straw that broke the camels back I guess. I left and went to live with my grandma but she couldn’t do much as she is old and a very stressed person. I think this is when the depression set in? I cried so much after leaving him because I loved him more than anything and I’d had a baby with him and I thought he loved me and I still think at times he did. When he wasn’t lying, cheating, manipulating and gaslighting me. I know this sounds stupid because it is but I do think sometimes he cared and I felt safe with him and I’m not sure why. So anyway I left my grandmas after 2 months as it wasn’t suitable for me and my son. I got a place of my own at 17 with my son but I started to get really really depressed I couldn’t get out of bed I wasn’t eating I was taking long showers just to spend time with myself, my dad was living with me across the country to help and started taking my son back over where he lived with my mother just so I could have days to myself but he thought I was being lazy and couldn’t be bothered and just basically not wanting to do anything because he would do it instead. He didn’t know I was suicidal and hurting myself. But I still looked after my son the best I could when he was there with me. One night I got really drunk and got very bad and my friends had to call an ambulance because of how suicidal I was (my son wasn’t with me at the time) anyway my son went over to be with my parents and I went up to see him on weekends. I couldn’t handle it I felt so lonely and I didn’t feel I could look after my own child. It hurts because when I was with my partner I did everything morning and night and I was fine and happy to do it even though I was struggling I did it and even though I found it so hard I was happy because he had a father there. I am now living with my parents back in the same part of where my ex lives and I’m worried sick incase he finds out I’m here. I have no friends or people to talk too. 1) because I’m scared theyll tell him where I am. 2) because all I can do when I’m here is think about him and how it could’ve turned out and everything he did to me. Anyway my parents mess with my head, they tell me I don’t know what I’m doing. That I over reacting and that they know my child better than me. I know how I want to parent my child and how to make him happy (they’ve even said they’ve not seen happier than when he’s with me) but for example today, he’s really sick not eating drinking much etc and has been like that 4 days now so I wanted to take him to urgent care. They said I was over reacting and making it all about me and that I always make everything about me and that it’s boring, even though I was stood in front of them crying my eyes out worried sick about my baby. My mother even said I’d be sectioned for being mentally ill because I wanted to take him to be checked up on? They use my own child against me to stop me doing things. I said I wanted to take my son back to where I was living and my mother said she would call social services and I’d have him taken off me? I’m so frightened of this because they know I have previously felt suicidal. But I cannot live here my parents make me feel so incapable and stupid and that i can’t look after him without their help. But what messes me up is my ex partner said they do this and I tried not to believe it because they’re my parents and they adopted me, even though I was in and out of foster care because of them I’d like to think they loved me. They said bad things about him and that was all true but they wanted me to leave him and they pressured me into it and now the police are involved etc. I can’t help but feel guilty because I still love him even though it wasn’t healthy I feel horrible for leaving the way I did especially when I didn’t really want too in the end I just needed a break from him. Now I see how toxic it was but I still miss him everyday and I can’t move on it’s been nearly a year and I still love him. I can’t keep relationships or care about anyone because of how he messed with my head but also because of how much I miss him even though I think if I saw him he’d want to kill me now. I don’t know how to feel much anymore, my son woke up earlier and was screaming and wouldn’t stop but I didn’t feel anything, I just got angry and annoyed inside my stomach. Like I just wanted him to shut up and go back to sleep but I didn’t feel any sympathy or worry I just wanted him to be quiet. Please can someone help, I’m really honestly begging. I know I need help but it’ll take a while to get and I need advice for now, I need help with my head but also I dont know what to do I can’t live with my parents any longer it’s making me worse, they manipulate and lie too. Please please help.