I had a water bottle in my bag for 4 day than i drank it tasted like plastic but i only had a sip should i be worry i have really bad anxiety?

WORRY: Sounds like you don't know how to measure possibility against probability. Most probably you won't be harmed. But if you worry a lot about the small stuff, get a therapist to help teach you how to sort it out.

Seek Expert Eval: Obsessions =unwanted thoughts that get stuck in ur head. They can spook u & trick u so that u come 2 believe the thoughts r real or that they mean something. They can also trick u into performing actions/rituals 2 chase away these thoughts ("compulsions"). See http://bit.Ly/ykpajd. Rational thinking/calculating likely outcomes not all that helpful. Exposure & response prevention = effective tx.