Need some advice...

I recently just found out that I'm 5 weeks pregnant. This is a completely unexpected and somewhat unwanted pregnancy. I'm in college and my boyfriend of three years is a recovering drug addict. I know most of you are going to say run and get away from him, but just hear me out before you do. I'm 21 and have custody of my nine year old sister because my moms a deadbeat, so is my father. I've been living out on my own since I was 17. When I met my bf he was financially stable, had a great job, etc. when we moved in together he completely took care of all the bills and I for once in my life didn't have to worry about money. He had to quit his job because they wanted him to relocate so he started  working for his dad who owns a business. His dad is very well off but acts  like a prick when my bf asks him to be paid for working, so he can pay our bills, although he always says "if u guys need anything let me know!" And of course if we do he's a jerk about it. So we have had some stress about money recently bc my bf hates asking his dad now, although his dad knows what bills we have and when they're due and he still always makes us beg. Anyway my bf started using drugs and it has continued to get worse and worse. I have stayed with him because I could not make it on my own financially without him, especially with my sister now and because I do care for him greatly. Now I just found out that I'm pregnant (UTI while on bc, did not realize antibiotics diminish effectiveness). Originally my bf said he wanted to keep it, now he's saying he wants me to have an abortion. This would be my 2nd abortion (I had one six years ago and have been careful since). I am really against ever doing it again, I really don't think I could do it. But at the same time, I don't want to have a baby under these circumstances. I know I could do it, because I'm resourceful and would have no other choice plus I have a great job. But my bf's family will be upset and hate me (they already do for no reason, bc they're foreign and I'm American I guess). I'm just under a lot of stress and I can't stop crying about it.