I'm 22 and usually with the girls I date I become the back up guy. I'll go out on a date or two and things seem great but then they start texting me less and say they aren't ready for anything yet. But they will want to keep talking to me and will get into a relationship right after.

The last girl went back and forth with me, she ended it twice over texts, came back a month later saying she may want to try again in the future but wasn't ready for a relationship. Also, we never reached the point of a relationship, we were just getting to know each other by going on dates and hanging out since we go to the same small campus, have the same group of friends and saw each other every day. She kept me around and was pretty much texting and snapchatting me all the time everyday but we weren't even seeing each other or doing anything beyond that. She would even act possessive when I would mention a random girls name. I finally decided to try and talk to her after a month and she got all flaky and said that she felt sorry for leading me on and didn't want me to hope for anything to happen. Said she wanted to be friends at the least and was ok with me bringing that all up.

After that I put the brakes on the texting and snapchatting and she would try to get my attention by sending me snaps every other day. When the semester started she gave me the silent treatment and would ignore me. She is now just starting to get better since she thinks I have been talking to other girls but she still acts weird around me. She does give my guy friend a lot of attention like she used to give me when we were seeing each other and even got visibly annoyed the other day when me and her girl friend were talking a lot about music. She is also always the first person, or one of the first, to look at my snapchat stories every single time. I have been trying to get over her but seeing her isn't easy and I don't really know how to act around her. We have a close group of friends and we all see each other and hang out all the time so I'm trying to be friendly but her behavior makes it difficult.

Because of all of this I don't know what to do anymore with dating. I'm super busy with school and I'm working on gaining more weight and working out so I can't find girls to talk to, I go to a very small off campus site. There are a few girls at my campus I would love to talk to but I don't know if that would be weird if they weren't interested. Anyways, I don't understand the girls that do this. This girl clearly wasn't interested, got all weird when I asked her about us, and then pretty much started hating me. But if I stayed around and kept talking to her all the time then I'd be that guy that she would have on the hook. How do I avoid all of that and actually get into a relationship?

I feel like I screwed up my chances with her and that's how I ended up here. When I talk to my guy friend about her, he doesn't believe she has any ill will towards me and that she must think I am still into her so she is acting weird around me because of it. He also doesn't see anything that she has ever done as anything wrong so I second guess myself on everything that has happened. I just feel like I am the one who has screwed up everything I had with every girl now because of this. I just don't know what to do anymore. I have never been in a relationship and I'm still a virgin as well which doesn't help me. Any kind of advice would be appreciated.

Tldr; I always become a girl's back up guy, I of course move on but I don't know how to avoid that in the future again. Am I the one causing this to happen or is it the girls? If its me then how do I fix my problem?