What to do with this mess of a breakup!!!?

So I dated this girl from work, shes actually my lead. We dated for about two months. Shes 19 and im 22.We had to keep our relationship a secret at work. Things were great for a little bit until i caught her texting another guy from work things she shouldnt be talking about. I confronted her and she apologized and said she'd change. Everyday at work though she would still flirt with him. He didnt know her and I were dating, so on occasion he would come up to me and say things like" i really just want to have with her". But i couldnt get angry because i had to keep the relationship a secret. So i started to become less and less involved in the relationship because she was such a flirt and i was not ually attracted to her and she had a smell down there. Until the day came when we decided to take a break. So after a few days of the break she wanted us back and I agreed but asked for a lil more time. Well after a few days I was ready to start the relationship again. But all the sudden she didnt and she was dating the guy i caught her texting wrong when we were together, he also told her i cheated on her which is bull. She says they have only kissed and he was there for her so thats why. But this guy who i work with by the way is a huge liar. He's 18 and lies about everything. I confronted him the other day and he tells me that they have kissed and he has had to fight her off for and he told her i cheated on her which i never did!. So i told her everything all the lies he said about her and how he told me all he wants to do is have with her, but she still is wanting to defend him. after all the bull he is filled with. I dont understand. She tells me there not together but she wants to hang out with him and she needs space and time to be single. Is this all bull? Is she actually with him and thats why she doesnt want anything to do with me. She would tell me all the time she loved me and we are meant to be together but a week after we "took a break" she moved on to him and we all work together. This pain hurts so much i dont know what to do. I want her back so bad but now she is nothing but rude to me. And says her decision is made she wants to be single, but a week earlier she told me she loved me. I havent eatin in two days and cant sleep im so hurt and i have to see them two at work everyday. What do i do???