How I was miss diagnosed for 13 yrs. Have you ever been told that you are ill and the test had been done and you are told you have an illness?

The medical professionals say, we did a test and we found that you have an illness. Every time you question the Drs they say when you are going to accept that, what we told you is real.
I was on treatment for years of a disease I did not have. I started doing a research about my illness, until this year, I found a Doctor who said I can re -test  you and see if you are sick .I never was sick of any symptoms of that illness. When this Dr did a re-test I was found with no evidence that I had the illness. I need help? What can I do with such a mistake in a medical field? I think there are so many people who are treated for the wrong illness cans somebody help.  What should I do with something like this?