What Causes Itching And Burning Sensation On Body?

Hello, I had a "risky" sexual encounter almost 9 weeks ago. 12 days later I attended a STI/GUM clinic. A swap showed the presence of pus, i was therefore given a course of antibiotics. I also took an HIV test which was negative. I have been a nervous wreck since. I took another HIV test at my doctor's at 27/28 days which again was negative. Since then I have developed a burning sensation in my neck, hands, forearms, feet and lower legs. Over the last few days I have also become itchy all over my body, there doesn't seem to be a rash. My doctor feels all this is due to the stress, anxiety, not sleeping well etc. I would be grateful for your opinion. I am due another HIV test in just over 3 weeks.