maybe tmi- Crotch sweat or fluid leaking?

I'm 38 weeks pregnant and have been constantly waking up in the middle of the night covered in sweat. Well, tonight i woke up and my underwear felt pretty soaked. My bed didnt feel wet or anything so I didnt get up (even though i guess i should have lol). I'm just not sure if it was crotch sweat or fluid....but now I notice that i have pretty thin, almost watery discharge. I have an appt at 10:30 this morning. I guess i should mention it to my doctor? Or should I call the office when they open and see if they want me to come in sooner?