Amniotc fluid does not smell like urine, or your usual
discharge, and has a viscosity/slipperiness like water and not cervical
discharge, if you're in to self-diagnosis enough to check out your undies.
Having the fluid checked for amniotic fluid is not a big deal - I had it done when my water broke at the onset of labor with our first. They swab the liquid and do pH or similar test. It may have taken about 5 minutes?