I have hypochondria but i accidentally touched a chewing gun few weeks ago and washed my hands right after. should i be worried?

No: Germs don't survive on hands more than a few hours if you do nothing. If you wash your hands and/or use a hand sanitizer, their life span shortens, but its unrealistic to think any treatment will kill all the germs on your hands. We live in a germy world, but we also have very good natural defenses, starting with the skin. Go to a psychologist for the mental part of this condition.