Am i going to be a drop out forever?

Okay, well here goes, I guess it all started when my mum and dad splt up, i was about 5 years old and we moved to to a bigger city from a small town. We lived on a rough council estate and things started to go downhill.
My mum was a heroin abuser for 7 years and attempted suicide 3 times. We were taken off her by socal services but i was allowed to remain in contact with my dad. He was my rock. We were sent to live with someone else, me, my sister (4 years younger than me) and my Brother, who suffers from learning difficulties and anger problems.
My mum won custody after 9 months and when we moved back she was living with her Boyfriend. They have been together 12 years now. I hated him in the beginning and found happiness in my Aunt. I kept running away so eventually we moved away to the other side of the city and as a child thats a pretty long way. My dad lived with my Grandad, he was like mmy best friend, i thought he would live forever. He didn't. He was the first dead body i saw, i was 14. Afterwards my Dad started drinking heavily and got laid off work. He's an alchohlic now, with chest problems and Liver Problems. I constantly think of him dying. Things didn't improve with my stepdad so the first chance i got i moved out of my mum's house and moved into a flat with my boyfriend of the time (who is still my best friend), i was 15, he was 19. I did well in my GCSE's, gettin all A-Cs, after school i went to college but dropped out after 9 months, to get a job to pay the bills. I got a good job, but i hated the people and after a while i snapped. So now i'm a shift manager for McDonalds and i hate it like you would not believe.
Last year was the worst year of my life, i lost 6 close family members, got evicted, got a promotion (wish i hadn't), my cieling fell through and all of my stuff got wrecked, i had nothing.
I just feel like i don't amount to nothing, i want to do something great with my life and i don't know where to start. After losing all my family, i just keep thinking whos next? Praying it's me, so i don't have to deal with the pain again. I can't watch my family fall apart again, i have to no one to turn to, i feel so afraid of life......