can you be in labor and not know it?

This may seem like a super dumb question but can you be in labor and not know it? I'm a super anxious person so I over analyze everything! I'm 36 weeks and today I noticed I felt this "wet" feeling all day almost like when you think you're starting your period. It doesn't seem to be anything soaking through a pantiliner or anything but I worry it could be my fluid leaking! They usually tell me if it's a leak it would soak a pad in an hour and it's nothing like that. 
I went to the hospital 2 weeks ago for a sudden gush of watery fluid the tested it but it turned out to be discharge. I also feel my stomach is super tight like I ate too much. Doesn't hurt I'm just uncomfortable. I plan to call my doc in the morning (my next appointment is Tuesday)  I just wondered if someone could be having contractions and dialating and not notice. Last week I wasn't dialated or effaced at all.