I had that a week ago after class, turns out it must have just been sweat. Went to the hospital and tested negative for amniotic fluid. Midwife told me next time to put dry undies on and lay on my side for half an hour. When I sit/stand up if your panties are soaked again it's most likely your water and to call l&d.

the tightening is probably BH

your water breaks usually little by little and it just feels like your peeing, the dramatic "gush" is just something that is on TV rarely happens. if ur stomach is contracting too,you might be in early labor! who hoo! just start timing them and let your person know or call your dr