Your risk of acquiring anything was virtually zero, based on your description of the encounter. No STD can cause symptoms within 8 hours of exposure. Gonorrhea and chlamydia are not transmitted by towels, toilet seats, etc. It doesn't matter whether the condom was latex or something else; the risk is still zero or close to it. The polyurethane condoms are every bit as effective as latex ones.
If you have otherwise been sexually active in the last year, getting routine STD/HIV testing might be a good idea. But I do not recommend it this encounter is your only risk in the past year. You do not need antibiotics, but in any case such treatment would not affect the results of HIV testing.
HHH, MD
I am not a doctor, but this doesnt sound like a risk. I do know that antibiotics WOULD NOT effect a 5 week result. The doctor is going to tell you you are negative, and with a 5 week test in hand, you will continue to be negative all the through 13 weeks. Not sure if it is a fact or not, but he has said MANY MANY times that he has never seen someone test neg at 6 weeks, then postive later on. So just relax, and smile.
I have read the doctor post many many times that no STD will show up in 8 hours. Also, if the condom was on and did not break there is Zero chance you caught a baterial STD. I suspect you are "hyper aware" of your penis right now and feel every little thing and your mind magnifies it. Also, I have never heard of dark urine as an std symptom. I think the doc will say you do not need testing unless it is to relieve anxiety.
I'm 100% with imdumb. There is absolutely no chance you contracted anything from that encounter.
As for the color of your urine, you're probably a little dehydrated. Drink more water, and I bet it'll lighten right up :-)