Hello Dr, I had unprotected sex with a sex worker 6 months ago and I tested 7 times all come negative first test was after two months exposure and la?

Testing? Are you testing for pregnancy? This sounds negative. It remember there are other issues. There are many sexually transmitted disease. Now you sound concerned so go see your doctor. Get examined and tested and ease your mind .
Fine after 6 mo. if you had all the STD work up repeated after 6 months and its negative then you should be fine.