Puzzling, returning issues with UTI(?) symptoms.

Patient: I am a 21 year old male. Around six months ago I was having symptoms of a UTI, including a small amount of yellow-ish penile discharge upon waking up, and periodically throughout the day between urination. It usually would not be visible during the day unless forced upwards, but it is still present. I visited my physician who tested me for Chlamydia as I am sexually active with my girlfriend and she gave me a one-time antibiotic FOR Chlamydia just to be on the safe side. Upon taking the antibiotic, it cleared up and went away, however the test came back negative a few days later. So i’m not entirely sure what I had, but it was cured with this antibiotic. I’m now having the symptoms yet again, except now there are small, skin-like particles in my urine as well. It does not burn to urinate, however it does feel slightly different than normal on occasion. The urine is also not discolored in any way. I eat decently healthy and drink 2-3 bottles of water daily. I do not smoke or drink alcohol either. I do have unprotected sex with my girlfriend, as she has had the procedure to not have children, however we both urinate directly after having sex, and we both stay clean as can be. I assume a UTI, however there is virtually NO pain or discomfort, and if I didn’t force upwards on the penis, I would hardly even notice the discharge. This worries me as to how long it may have been there and I have heard tales(s) of it leading to not having children and severe issues if not treated. I would visit my physician again, but I do not currently have health insurance and the last time was quite costly. So i’d like to have a possible idea beforehand this time so i’m not just throwing money at a trial and error situation. Any ideas of what I may be dealing with or how it returned? Remember it was once cured with Chlamydia medication that actually returned negative. Thanks!