Need to get this off my chest and ask for advice

As-salamu alaykum, everyone. I'm pretty young, I guess that's how you'd describe me. I'm going through a really tough patch. I feel awful about myself in every way, and my life's a complete mess. I grew up in a very abusive home, and being the eldest comes with all these expectations I'm supposed to meet. I don't have a good relationship with my parents or siblings, and I just stay locked in my room all day. My studies are going terribly, I'm failing, and I can't focus on anything-my head always hurts. I keep falling into sins, and no matter how hard I try to stop, I end up back in the same pit. I haven't been praying much, only Jummah. Over a year ago, I was praying five times a day and didn't miss a single Salah for eight months, but now I don't know what's gotten into me. I can't seem to fear Allah or worry about the sins I'm committing, even though I know how bad they are. I want to come back to prayer, but I keep failing. I tried to start again last Friday, but I only managed Fajr and Jummah, and then I lost track of the other prayers and missed them, and I haven't prayed since. I feel so guilty. I'm stressed about my future-whether I'll get good grades, get into a good university, and find a good job. My father is quite old and close to retirement, and I worry if I'll be able to provide for my family after him. We're not doing well financially now, even though we used to be well-off. This worry keeps me up all night, I can't study, I lose focus, and I've lost so much weight. I used to go to the gym, but now I just hate myself and what my life has become. People I thought were close turned out not to be, and everyone has left me, so I don't know how to help myself with everything piling up. I'm in tears writing this. I just want to be a normal guy, at peace, close to Allah. I don't know what's happening to me-I feel very suicidal sometimes, and I'm sorry for venting. Thank you if you read all this, I truly appreciate it :)