The easiest way to tell if you're leaking fluid is to walk around in the bathtub (or any hard surface) w/o your panties on. If you get a continuous drip with each step you take, it's fluid. If it comes and goes, it's pee. Pee will eventually stop... fluid won't. That's not fool-proof, but it's what the nurse in my childbirth class told us to do.
Either way, if you think there's a chance it's fluid, get it checked out! Better safe than sorry!!
Good luck on your section!
And WELCOME TO JM!!