Pee, sweat or waters?!?!

Okay so i could be being really paranoid about this, but usually I feel it when I pee myself. I went to the toilet earlier and there was this quite big wet patch on my underwear. As it is hot at college today it smelt of sweat (sorry tmi) but usually I dont create actual sweat patches down there, and I don't have hair there if that makes a difference. Is this my waters leaking? I'm 30+4 weeks