I had a sex encounter, the first one in my life, and had oral sex as well, where i licked the sex worker's vagina. I think i had a little ulcer in my mouth at that time. After around a week i started having pain in thighs and in my lower abdomen now after around 18 days i have this freaking sensation near my penis region. I dont have any other symptons or pains till now, no rashes, no fever nothing else. But i am really freaked out at the thought of HIV. Can you please advise as to what this could be.