What should I do? Girlfriend really hurt me?

So I've been with this girl for almost a year and its been great. I was in an accident like 7 months ago that almost killed me and spent 2 months In the hospital and she was there for me the whole time and stayed faithful. She's never cheated on me to my knowledge and she's been fine with staying in with me. I have trust issues due to her having a thing with me and another guy before, but that was before we dated. Now our one year is in a month. And last friday she basically broke my heart. We were supposed to hangout and she was gonna go to her friends and I was gonna pick her up to comeover. She told me she couldn't come out. She stops texting me and is barely answering me I'm getting nervous but she says she's just on tumblr and that she's home. Then I call her house and her mother tells me she's at her friends..my friend texts me minutes later that she's at a huge rave and he saw her dancing and kissing guys. My heart was broken. I freak out and dump her. On Sunday I take her back, but I'm still not over it. Currently 5 kids have told me they saw her there dancing with guys and whatnot, but she swears she didn't and denies it. I just don't know what to do, I'm getting surgery next week and even though I can walk and stuff again ill be out for a week or so and I think I'm just scared to be alone through this. She's been here for me so much and been an incredible gf up until now. She lost her virginity to me and I never thought she'd ever do anything like this. Her defense is that I never let her go out and that's why she lied, but there's a reason I don't and that's because I don't trust her and she acts different around friends and she proved my point. She told me she's gonna stay in with me until I'm better and trust her again and that she's sorry and it won't happen again but to be honest..I dont think she's sorry. She said she spent half the night crying in the bathroom because I found out relatively early into the rave and dumped her. She spent the whole night calling me and I ignored her. But now she's posting pics of night and she looks happy in them not like somebody who was feeling guilty or upset. And when I bring it up she just gets defensive, I don't think she's sorry. I'm with her because I'm scared to be alone and I love this girl to death and I just keep wishing things will be okay and back to normal, but they aren't yet. And she bought the ticket a week in advance so she was planning to lie to me for a week..I don't know what to do. I know she loves me, I just don't get why'd she would do this. I know she did, I just wish she admit it. I forgave her, but idk..what do I do? Leave or stick it out or just be with her until I'm healthy again? My trust for her is gone and now I feel so inferior because I can't dance yet like these other guys idk help