Feelings are neither right or wrong. They just are. It is what you do with them that matters. You may need to talk to a counselor or someone about this to get a professional perspective. This is a tough issue. You have to have trust in your school to send you kids there. Where ever you go. Your ability to trust any school has been rightly shaken by this event. That seems logical to me.
However, what alternatives do you really have? If you had your purse snatched would you never leave your house again? Maybe for a couple days, maybe at first you wouldn't go out at night, or alone, but would you never leave again?
Of course it is much easier when it is your life, than when it is your kids lives. I would check out the rules of the school. My kids go to catholic school, and after all the priest issues, they now have a program to train people about these issues. We also have some strict rules about being with children --- never alone, & always with the door open. I am not saying bad stuff won't happen at our school, it could, but I know more now that I took the class and I feel better prepared to keep an eye out for questionable situations. Knowledge can some times help over come fear.
This is hard. Best of luck.