I had unprotected sex from this girl at my college. She said she was clean (although some people don't get some symptoms of some disease), and almost immediately after sex my penis felt weird. It feels warm (specifically at the tip) but it does not hurt. I have not experienced any pain or discomfort peeing and there is no discharge. The warmth seems to be a symptom of chlamydia but it's seems weird to happen so fast? It happened about 4 days ago and it doesn't really go away, although not too noticeable. What could this be?