Want to know. Bcoz i have high tsh.

I had an sexual exposure 2 years back.from then i never had any sexual intercourse..that was an unprotected sexual intercourse.from then i have more than 10 HIV antibody test and all of them are negative.my last test 1 and a half year post exposure it was also negative.besides i have all sorts of STD test and they are also negative.is it possible to have false negative test..bcoz i have had some itchy rashes its comes and goes by its own..it comes in smaller number it comes in 2 or 3 in number..i also suffered from scalp pimple it also comes in 1 or 2 in single time..so should i worry about HIV or should i relax..what could be reason behind those rashes are those serious or could be due to seasonal changes or hormonal imbalance bcoz i have high TSH...reply as soon as possible..