OK there's this girl I've been going out with for a couple of weeks now. We met at our school orientation and things went pretty well from there. We hung out all the time. We'd go study together, movies, the mall, and I'd go to her apartment frequently. (I would wait for her to get back from work and clean up for her...)

Anyway, recently she's been pushing me away. She doesn't want to reply to my texts or answer my calls. I shared/made posts on Facebook to give out hints that I didn't like it. (Posts like, "talk to me if there's a problem, I'll listen. Blah blah.) It's been going on for about a week now. I did try to visit her to try to talk to her, but it never ends well.

Then today something weird happened. My close friend asked me about our relationship, and I said things weren't going well. Then she told me that her friend (a guy) slept with my gf (I'm a girl, openly bisexual).. Honestly I don't know what to do anymore. Should I believe it and leave it like this, assume it's over now? I've begun to doubt that this was real between us and think that she thinks she's better off with a guy. She made me really happy, and I'm sure I made her happy too. :/

I'd recommend that instead of trying to give hints through facebook posts or any other beating around the bush, just go find an opportunity to ask her straight up.

Are we still dating?
Do you not want to be my girlfriend anymore?
Did you sleep with this guy?

You're not gonna get anywhere by making facebook posts. And honestly, it might not be what you want to hear but I don't know if you should be so sure that you made her happy too. I'm not saying that you didn't make her happy, but often times our perceptions of others aren't completely accurate, and also people's emotions and feelings are extremely complicated which makes it hard for not only others but themselves to understand at times.

But with that being said, I don't think you should give up if she's not feeling happy. I think you should then ask her why she's feeling unhappy, and try to work things out and fix things. And maybe she herself doesn't know why she's unhappy, and that's normal. You two will just have to put a lot of effort into building your relationship.

Anyways I wish you the best of luck.

Yeah and think : if you win your relationship will be the best :)

Using technology AKA INTERNET, people might not believe what you are saying. For example: I Love You. For all the person knows, the I-Love-You-Giver person can just be lying. Some people says I-Love-You just to get in your privacy, and leak them out.
For Example: The person will ask for you pictures. Then after that, you want to break up with him/her, but he/she threatened to put your pictures online if you break up.

She might also be pushing you away just to protect herself from something/ someone. For example: Heartbreak.

Anyways, I would recommend you to ask her straightforward in why she's feeling like that. Maybe give her something romantic like love letter or roses with a message of you wanting to get back together.

My advices aren't that good, but I wish you good luck.