STD test was clear by the way
It sounds like stress more than anything. I have read a lot about STD's due to my own dumb mistakes and have had a bad reaction to the situation. If tests are clear then you are ok. I am not sure on testing methods and what Dr's will ask for, other people here are better at that. But just be happy that tests you took were negative and possibly seek a thearpist if things continue to both you. Also God is always listening.
You don't have an std, as your results showed, and no std would cause the symptoms you are having.
Follow up with your doctor, and please seek help for the anxiety if you need to.