Really need advice please!

I'm going to try to make my story as short as possible, but its a little difficult to explain.

So my parents divorced when I was young and I stayed with my mom for most of the time and saw my dad on weekends (like what usually happens). My mom and I never got along. I think we were just too different. I am very much like my dad and I think part if the reason they divorced was because they were so different.

So my mom used to yell at me because I'm not religious and I "never gave it a shot" even though I went to sleep away camp that was very religious for a week. I was never rude about being a different religion but she couldn't come to terms with it.

She is (or at least was) a very immature person and anyone who knows her would agree. She takes advantage of my grandmas generosity by taking her money (sometimes without asking) and my grandma has bought her cars and pays her phone bill etc. Eventually I stopped talking to my mom when I was 16 mostly because she was always with abusive, alcoholic druggies and I was stuck witnessing everything (I was too young to drive at this point but it went on for years).

I still talk to my grandma (mom's mom) and she is so distraught over us not speaking in almost 5 years now. now I'm pregnant and no one knows but I don't know if I should try to talk to my mom again? I'm only thinking about it because I know it kills my grandma and now my mom won't meet her grandchild if I choose to continue not taking to her. I've been very content with not being in contact with her these past five years. Should I see her/talk to her again?

Sorry this is so long, I just don't know what to do. Also I don't think she's still around druggies but I could be wrong