Feeling guilty?

I have a best friend...or used to be best friend...who I've known for 15 years. We have grown up together, lived houses down from each other and would spend days with each other and the others family, and basically became attached at the hip. When I was a senior in high school, we would skip school and do stupid stuff. Just for the joys of rebellion. We started smoking pot together, for me it was just fun, for her it was a crutch. When it got bad and I wanted to go into college, I chose community to stay at home and away from the party life, and I have stayed away from drugs and alcohol completely since. She went off to a university and got worse. Uses drugs and alcohol like water to keep her alive. I stayed out of it because to tell her she's wrong, would just make her want to do it more and I knew that's part of college. When I got pregnant, I knew I had to step up more, and make compromises with my SO. Instead of supporting me, like I have her, never once telling her she was wrong, she told me we were stupid for making an agreement to not get pulled into drugs or alcohol. To limit ourselves whenever we actually get the opportunity because of his families alcoholism, and me not wanting to be messed up around my infant. She said he was controlling me, and I said that I guess that means I'm controlling him too. She said we were perfect together and congrats. Then went on to ridicule me for the choice we made. I feel guilty for wanting to step up for my kid, and feel like the one person I thought would always be there, would rather be completely wasted then anything else...she only chooses to come in my life when it benefits her...and now I feel stupid. Sorry, I had to share because it hurt. A lot.