Advice for dating a drug addict

My boyfriend, and now babies father, is a drug addict. He was clean and doing very well for the last 2 years. I found out I was pregnant in September and it seems the day after I told him, he began using again. I have dealt with it this long and have tried everything I know to help. He has used almost everyday since I told him. I have never done drugs so I don't understand and freak out every time I can tell he's messed up. The other day he stole my credit card, my debit card and $60 cash. He spent over $500 total. I am a full time student and work part time as a waitress so that money was literally everything I have saved and the money on my credit card technically isn't even mine. His mom convinced me not to call the cops but I tried to kick him out and he won't leave. His name is on the lease too so he keeps telling me I can't do anything about it. As an outsider looking in, is there anything I can do? I can't leave. I have no money and nowhere to go. Also am I already a bad mom for not including him in my pregnancy, even though he only had tried maybe once? Some days he says he doesn't care and doesn't want the kid, then other days says he will take the child away from me the minute he can. I'm just confused and scared and need some advice. Thank you!