@Jasonnow,
Visit another medical doctor and have another HIV test done, for your own peace of mind (I doubt that you have HIV, by the way. I think you just had a urinary tract infection and nothing more, but there is nothing wrong with being sure).
And then ask for a referral to a mental health professional. I think you're being consumed by guilt about your infidelity and it's being manifested as health worries and some generalized physical symptoms.