Search Results: girl suddenly stops talking to me

So yea I've known this girl from high school now we're in college and I was always super outgoing with girl in school and flirt around til senior year I began to have classes with her and I got 'serious' especially when I'd catch her daily looking at me but she'd quickly look away, at times she'd try to keep the stare... again she's known to be quiet and she secluded the whole high school years.
My friend told me many time she'd look at me when I'm unaware and she's a gorgeous girl, I like her so much BUT... ME, I... YES ME!!! I BECAME SHY AND NERVOUS EVERY TIME SHE'D BE AROUND (I was like the most confident and popular in my group;15+kids... I was never shy) I never manned up and approached her to talk to her in the whole year and she even asked my closest friend a lot of info about me... anyways boom we happen to end up in college then I eventually said hi to her and we had normal convos she opened up talked about high school and her family lol... then suddenly after a week she stopped talking and it became high school again she'd always look but no talking, neither did I. A year later I stumbled on her social media I added her she instantly accepted and followed liked my pictures messages me etc... but then I crash into her a while later in college she walked by no words I said hi and she said hi... looked away, walked away!!! WATTS! then I confronted her on chat that night she said o I didn't notice you but she even said hi back, makes no sense... and told me she was go. then eventually after few weeks we had a small argument and then it got 'awkward' so we hadn't talk since then ;((. Now recently I go the restaurant she works at and again she would steal glances a lot, PURPOSELY walks by me many times when she could've just took the shorter path to her places at work and eventually asked me 'hey can I get you anything' in a very soft voice she usually doesn't speak like that with her co workers and she looked nervous and didn't hold stare... what should I do?