Sadness, I'm so sorry for what you're going through. When I read stories like yours, it brings home what a selfish disease alcoholism is. My dad was an active alcoholic and a very angry, unpredictable and difficult man all my time growing up but I was lucky to have a loving mum and sisters.
But I do know the feeling of HAVING to get out of the house and just hanging on, counting down to when you can do it.
All I can say is hang on. My determination to get out of the house meant I had an absolutely blinding focus and ambition to make it through university, get a job and build my own life so I would NEVER have to go back to that kind of hell and NEVER be dependent on anyone.
In the meantime, look after yourself as best you can. Detach from your mum as much as possible. I also urge you to get whatever help you can get, through the Family and Friends forum we have here, Al-Anon and a counsellor if you have access to one.
You absolutely can make it through the last two years. You can. Focus on the future you're building for yourself.