possible leaking 28w2d ?

This might be tmi... last night I woke up to pee and when I went to the bathroom I noticed my underwear felt a little bit damp. I just kind of made a mental note and brushed it off, because i figured its possible it can be sweat too (for some reason ive been waking up covered in sweat. gross, i know.) There have been a couple times since yesterday where I noticed that my underwear was a little damp, but I don't feel a trickle or anything coming out. Is there a way I can figure out of its discharge, leakage, sweat, etc.. without having to call my doctor? TIA!