What Is Yellow Discharge On Penis Tip Upon Waking Up?

im a 24yr old male and i went to see a doctor yesterday because ive been having an itch about 1 inch inside my urethra, but i havent noticed any discharge. he took a urine sample and squeezed the hell out of my penis, but still no discharge was present. he said i had "white cells" in my urine and told me i had prostatitus and he prescribed me ciproflaxacin @ 750mg twice a day for 2 weeks. after taking 2 pills yesterday, i woke up this morning and noticed that i had a yellowish discharge at the tip of my penis...why is this? is it normal? or do i have something else?