So I have a friend. We've been friends for over a year and we were REALLY GOOD friends. We did everything together. She made her former boyfriend quit drinking, then when they broke up she started drinking.. She also became friends with some people who aren't good influences on her. She has done drugs, drinks and has sex at 16 years old. Her new boyfriend is nice but he isn't a good influence and takes up a ton of time. She always ditches me. I feel like I am there when she doesn't have anyone to hang out with. We've been fighting a lot and I want to know what to do. I am so clueless, but something needs to change.

Sometimes being a good friend is being there during the bad times and sometime you don't see them during the good times but you stay the good friend.
If you think this friendship is one sided, stop being there for her. If she truly is a friend, be there, if you are feeling neglected. Talk to her about it.