Take some advice from a sophomore in college, if it helps.
when you've been hanging out with a girl for a few months, it feels like forever and you feel like there's something major there. I know that feeling, been there done that. The thing is, eventually and always, this sort of situation you're describing will happen and it's always the girl that ends up being bored. Here are some things ive done to Get Girls back wh are in your situation:
FIRST AND FORMOST- You shouldn't appear shocked or upset. once you do, it's you chasing her instead of the other way around. Next time you hang out with her, don't give her as much attention as you used to. Appear indifferent to what she said. Hell, when I was in your situation I would text a few girls before I would go and hang out with the problem girl just so that they would text me back when I hung out with her. She would see that i'm talking with other girls.
- hang around lots of women, all the time. Be social, be sure to keep constant communication with many girls at once. Even if you're with this girl, she has to know that she can be replaced. You will find a better girl out there, there always is.
- **Don't be needy. Don't ask her what she's doing all the time, don't ask her to explain why she did something, etc. once you show neediness, it's a major dlv. Especially in your case, don't be needy at all, don't initiate communication anymore, wait until she contacts you.
- Be spontaneous. This doesn't mean you have to try too hard to impress her or to do something crazy, it just means that you have to start changing minor things in your life. Everything else will come naturally. with me for example, I started to work out more, joined an intermural frisbee team, and started to more actively make friends than before.
-Be decisive. Self explanatory, don't ask her where you guys should eat tonight. you make the definite choice unless she says something. you don't do this, another DLV.
The bottom line is, become more social, social proof yourself, and make sure you've changed for the better. In my case, I did this and within 3 weeks the girl wanted me back but I had already moved on to a hotter, cooler girl. Maybe the same will happen with you 