Why Do I Have A Pus Discharge After Urinating?

Well?. It hurts when I urinate big time. I no longer see blood coming out of my penis after urinating, but I do have pus coming out more often than before.
On the 17th I visited my Doctor. He game me in a container mixed with water 400 MG Suprax to take it with food as soon as I get home. When I drank it, not even a minute I felt extremely dizzy, disoriented, feeling like fainting & with my whole chest, arms, neck, head & arms itching as well as having difficulty breathing (I know I'm allergic to penicillin).
The following day I started to take twice daily Sulfamethoxazole tmp ds.

It seems to me the antibiotic is not working.

What can it be?