Does she like me? I really like her?

Ok so i really like her, we did speak a bit. Online at first, found out we like the same music. I really like her. I approached her a few times and they were just quick hi's and questions about homework etc. Then someone found out i liked her. Rumours spread and i have no idea if she heard, although i bet she did. She never spoke to me about it and i stopped talking to her. Lately though she approached me and sat with me for over half an hour completely unexpectedly and i was so nervous all i could say was 'hi' after she first sat down. After half an hour of awkward silence and her sighing out loud alot and criss crossing her legs she got up and marched out of the room :/ oops. The next day i was sat with someone and she sat on the other side of her and laughed at all my jokes. Afterwards i was walking along behind her so called her name and she turned and i walked with her for just a few minutes and spoke about music. Still awkward though :( what should i do? I really like her