Not sure if she still likes me. what should i do?

so, i met this girl a while back, in a computer cl. she had a boyfriend, but still flirted with me occasionally. then, one day, she and her BF broke up. she was a mess, and was dumping the situation on this girl that sat in front of us. she moved to the back of the cl alone, and started to call me back to sit with her every day. she was always crying or upset about her BF for about 2 weeks, and i was the one who was there to help her through it. then, on the last week of the term, she started to get really flirty. we came up with an inside joke, that im her husbund. then the term ended and we got all new cles. i was fortunate enough to get a cl NEXT TO her. i was going to tell her i liked her on valentines day. i saw her before school that day, and she asked if i was going to sadies (in case you dont know, its a dance where the girls ask the guys, instead of the other way around). i, being struck by surprise, couldn't think of ANYTHING to say, but "no". then things got kinda awkward. later that day, when i was going to tell her i liked her, i saw her, with another guy. i was crushed. she rubbed him in my face a lot, but still talked to me when he wasn't around, and gave me hugs, and joked around about me being her husband when she was around her friends. then, on the last day of that term, when i was going to tell her i liked her, even though she still had her BF, both of my attempts that day, failed. now, since we have new cles again, i don't ever see her anymore. we don't talk at all now. she even has a new boyfriend (again). i saw her EVERYWHERE 2 days ago. first i saw her in my second cl. she said, hi, waved, and smiled. i did the same. she needed to talk to the teacher, even though she isn't in the class at the same time. i kept catching her looking over at me. then i saw her at lunch. she walked right by me, and started talking to her friends. again, she kept looking over at me. i saw her in the cafeteria. she made one of her friends move, so that she could see me between 2 peoples heads, from across the room. she kept looking over at me. yesterday, i saw her from across campus, and she kept looking over in my direction. then, today, i saw her between classes, and she was smiling, but didnt look over at me. mabey she knew i saw her. then, in the cafeteria, she got up with one of her friends, that i know, and they both walked by my table, and she noticed me both times, and smiled at me. do you guys think she's still, or ever was, interested? I'm not what you would think of as your first choice, definitely, and she is definitely more popular, and better looking than i am, so its very intimidating to talk to her any more. i just wish she would come up to me. iv never told a girl how i feel, and im most certainly not the most confident guy. what is your honest opinion of what she thinks/thought of me, and what should i do?