It sounds like you got a clean bill of health from your doctor. And maybe you miswrote the following "I didnt know that Oral sex caused HIV so easily" because the truth is that oral sex is not a mode of transmission for the HIV virus. If there is nothing physically wrong with you then I would suggest looking at the mental health side of things. Having tremendous anxiety can lead to a whole host of problems including a severely decreased appetite. It weakens your immune system and therefore you cannot fight off things such as the common cold as easily. Just a thought.
Problem is that I only allowed 3 months before testing. Its not my guilt, after that day my body feels strange.
Have you talked to this "woman friend?" Did you ask her about her STI status?
Oh...the health community in general is going from STD (Sexually Transmitted Disease) to STI (Sexually Transmitted Infection)