Does tooth polishing harm your enamel? i have had health anxiety about my teeth and went to the dentist for cleaning three times in six months. i then read that polishing can be abrasive to enamel. have i done irreplaceable damage?

Not irreplaceable damage but some. Your dentist should have advised you about the frequency and need for cleaning. Also you could/should discuss your anxiety with her/him. Anxiety about a particular health problem should be discussed with the appropriate provider and not acted upon by oneself.

You should set up a good oral hygiene program with your dentist so you don't need a cleaning every two months. Too much polishing with a strong abrasive can cause some harm but a healthy mouth and diet will keep you from a health anxiety problem.