Troubled Relationship with Mother? What Should I do? HELP?

To make a very long story as short as possible.... My mother and father have been divorced since I was a infant. They both remarried much better parters years later but my mom has always held resentment against my father for being a bad husband Towards me my whole life. My father finally past away in 2004 accidentally at 50 yrs old. Me and My father were close and I knew he would always be there for me when I was making mistakes basically no matter what I did HOWEVER my mother was always real quick to get angry frusturated and bitter whenever I would make mistakes that she was ashamed of as, or that angered her or embarrassed her that she would diss associate herself with me.

Four Years ago my mom caught me using drugs. As much of a bad thing that it was I was also going to college in the Masters Program and working at a restaurant everyday as a waitress paying for my Masters degree myself. BUT I was living in my mom and stepfathers home when my mom went through my room while i was at work and found my stash I had . When I got hm from work that night everything I owned was on the curb of the street and I was thrown out of my parents. 27 years old I began a life of endless moving from friends house to friends house to couch to couch. Basically Homeless!!! During this time I met a man who is now my fiance, we dated for 1 year and I accidentally got pregnant and decided to keep the baby. He is now 8 months old and my mother still hasnt met him because of the stash she found I had when I was 27. I am almost31 now. We dont talk, email , write or anything. She basically has written me off. What should I do? Should I just forget about it and move on or should I try to make contact with her?? I want to have my son know his grandmother but he doesnt now I dont know when he will if ever?? Whats wrong with my mom? Is it my perception thats wrong for thinking shes wrong for doing that?