I've had these friends before. The kind who only text you or invite you to stuff when they want or need you, but the rest of the time they are too "busy". Sometime in the fall I decided I wasn't going to sit around and wait for them to hang out with me. I don't need them, so why am I acting like it? After I made that decision I started hanging out with friends from work and it's been great! They are so supportive and genuinely care about me. Pretty much the only thing I changed was that I stopped reaching out to my old friends. It was always me putting in all the effort anyway so once I stopped everything just kindof dropped off. So my advice is stop reaching out, find some new people to hang out with, and only hang out with her if you genuinely want to (not feel like you should).
The stupidest thing about all this is that even though I am so much happier with my new friends, my mom still thinks they are the "wrong crowd". I'm sorry mom, but if they don't support me, don't text me, and basically don't do anything to maintain the friendship then they are the wrong crowd. I've tried explaining this but she still can't get over the fact that my new friends drink and party (Utah is a strange place...). Whatevs.
Anyways, hope you figure it out!