I'm Christian. Feel extremely guilty after doing something bad...for a very long time. Help!?

This has been happening to me for the last half of the year. It's usually something apparently "minor", as said by others. I worry a lot about little things that I do wrong, get hooked up on it, stress on it, and am completely hopeless. I start thinking of all the possibilities - like I feel that my life is a lie if I brought schoolwork home when it wasn't supposed to be done home and stuff. And I think people are going to die or get super sick if I don't handle food cleanly. Sometimes I'm not even sure what's right or wrong. My parents think I just worry too much over little things. Please offer some suggestions. I am truly sorry for some of the things I've done.