a month and 5 days ago was my las sexual experience, i havent had any pus come out my penis, i dont feel weird or anything like that, i had shyphilis tested, hiv, vdrl, everything was negative. since yesterday on part of the head of my penis there is redness could it be some kind of std?? or am i a paranoid s.o.b?? if anyone can answer this it would be great. thank you