Welcome to our Forum. I'll be pleased to comment.

With regard to your first question, there is no association of hot and/or cold fashions or feeling hot or cold with the likelihood of HIV or any other STI.  These are non-specific symptoms which may simply reflect your own physiology or could be a sign of something else.  I would suggest you first find out if these sensations correlate with your body temperature by getting a thermometer and checking your temperature from time to time including when you are having these sensations.  If you are having a fever, you should discuss it with your doctor in a general way but I would not worry about them as a sign of HIV or other STI. 

Second, you mention that your exposure of concern was limited to oral sex and was over three months ago.  Few STIs are transmitted by receipt of oral sex.  No one has ever been proven to acquire HIV from receipt of oral sex.  Further, with negative tests, I would not worry further about an STI or any sort at this time.  In the absence of other symptoms, I would not worry about an STI of any sort if I were you.  Specifically, I see no reason for you to worry about NGU at this time. 

I hope these comments are helpful.  EWH

It would be most unusual for an STI acquired following receipt of oral sex (or any other way) to not present until 3.5 months after exposure.  further, the discharge of STIs is typically seen before, not after urination,  On the other hand, sometimes a bowel movement can be associated with the expression of prostatic fluid through the pressure that accompanies a bowel movement.  I see no need to actively monitor this situation and would not worry.

This is m third response to your questions and therefore, as per Forum Guidelines, will complete this interchange.  This thread will be closed later today.  I hope my comments have been helpful.  Take care.  EWH