Hxtr is correct.
Go into work, be yourself. Talk to her a bit, ask her how school is going, what are the courses she is taking, which one is her favorite, has there been a lot if homework. Idle chit chat etc. Be friendly, but not over the top friendly. Don't push.
Do not go into work with the attitude that she thinks you are an asshole. Never ever EVER assume/guess what women are feeling and thinking You will be wrong most of the time. If you want to know what she thinks, Ask!
Ignoring her and not talking to her is only going to make it worse. Don't send her anymore text messages until you can have the kind of face to face conversations friends have. Like was mentioned, texts, emails, and FB posts are often misinterpreted.
Talk to the girl as a friend, don't ignore her.