How To Deal With This Jeaousy?

This girl and i have been starting to get a long more as she starts to like me now after we've been broken up after a one year realtionship. She starts to like me again, i decided to give it another chance. We hooked up on halloween and have talked and hung out before that. We were going to talk about us dealing and taking our realtionship a little further in person. Not exactly datin as she planned on walking with me afterschool talking about it. I saw her after school, and saw her talking to this other guy. It got me kinda jealous so i left and she texted me after saying i didnt walk her home. I just said i thought you were busy and i had to go to work so i left right away. She apologized actually and said she'll for sure talk tomorrow. i didnt reply after that. On facebook, i see this guy who she was talking to, started to talk to her on facebook saying shes a hottie and all that giving her attention. Its getting to me since shes getting all this attention from other guys. It makes me feel like she can get any guy she wants. Its really getting to me and making me feel like i shouldnt be with her, it makes me want to avoid her because im just so bothered that the fact so many guys flirt with her and want her