What should I do about this girl?

I’ve had trouble recently with a girl. I talked to her all summer long because I went through a rough period where I pretty much lost everything but my family, without them I’d be dead. I messaged her on facebook cause I saw she was going to my college. I got her phone number and we texted a lot all summer long. She told me several times that she wanted to hang out when school started back up. Now that school’s started up, two weeks in now, and she’s just recently become single. She’s giving me mixed signals that she’s either interested or not interested in the least bit. She’ll talk to me sometimes, but then sometimes she’ll never respond to me. She’s never answered any of my phone calls but that’s my fault for never calling her in the summertime. I really am attracted to this girl and have seen her once in person, but she was cheerleading at a football game. I have a class that she walks in to, when I walk out of it. Should I wait for her to go in and confront her and introduce myself? Should I keep calling/texting her? Should I confront her on why she hasn’t answered my phone calls or hung out with me? or should I just forget about her?!

I’m so confused!!! I don’t want to give up on her, but at the same time, I’m pissed at how she’s teased me!