Waters going or wee? Possible tmi

Tmi. Sorry! How would I know if I've just wet myself or my waters have gone?? I've just come to the loo and my underwear is drenched, but I wasn't aware of doing anything!? Just felt a bit damp when coming up the stairs. I have been leaking fluid for a while but I've just presumed it's urine. I'm 38+1 weeks.