I feel like my life is falling apart

Not even 1 month ago I said out loud what happened between me and my grandpa. Not even 1 month ago I found out about what happened between my sister and my grandpa. Three days after I went to the police and gave a statement because apparently my family has been secretly trying to fight this for like 11 years. I haven’t talked to anybody about this since that day. My mom has been on the phone with psychologists back and forth. I don’t know when I will be able to work through this. My sister is the biggest bully in my life right now. Whenever we talk she finds someway to make me feel terrible about myself. When I try to speak up she acts like she is being attacked and like her emotions are being completely discarded if I try to talk about mine. 5 minutes later she acts as if nothing negative has ever happened between us ever. I have D’s and F’s in school right now because of this. We are in a hybrid learning model because of COVID. Tonight my dad decided to look at our grades. He is completely ignorant to why I have D’s and F’s even though he knows about everything happening in my life right now. I get good grades on all of my tests but I can’t do or focus on any of the practice or homework. He was being so aggressive and insensitive when talking about my grades and how I just need to do the work. He said that my grades are due to my pure laziness. This made me feel like a piece of trash that has terrible grades. I sat in my room for like an hour and then walked out to get something to eat because that’s the only thing I could think of doing that I know would make me feel slightly better. He is eating popcorn while watching a movie and he says, “if you get a bowl you can have some popcorn,” in a calm voice. He acts as though nothing negative has ever happened between us ever. Are you sensing a pattern? He completely degrades me and makes me feel terrible for my grades and then acts like nothing happened 5 minutes later. My sister completely degrades me and makes me feel terrible about myself and then acts like nothing happened 5 minutes later. After he said that I went outside and sat on the porch swing for a few minutes instead of getting something to eat. I sit out there a lot whenever I am overwhelmed or just need some quiet. He knows this. Sitting out there I started to think and that never ends well. I started thinking about all the things I wanted to say to him. But when I came back inside I just had my hood up, walked by and said nothing until he asked if I wanted some popcorn. I just said a quiet no. At this point I feel like I’m telling my whole life story but if you actually read the whole thing I would really appreciate a comment, a suggestion or really any interaction.