Coukd it be a kidney/urinary issue? My niece had that. I can't remember what she was diagnosed with, but basically her bladder wasn't emptying fully. She kept going to the toilet but was retaining urine.
Another point - although it's normal for people to have stinging and burning with a urinary infection, some people don't, so maybe a doctor coukd check for that too?
Final thing - I'm paranoid about my children getting Type 1 too. One week my youngest was drinking and drinking and was all listless. I had that horrible sinking feeling that it might be diabetes, but her BS was normal. It turned out to be just one of those things.
So don't worry. Just monitor him and get a Dr to check him over as a precaution. Hopefully, everything will be fine : )