How to know when you’re in labor?

Morgan

So I was leaking fluid the past few days so I called my doctor on Wednesday & his nurse told me to go into hospitals labor & delivery unit to be checked. They rolled out the leak being amniotic fluid & said my cervix was closed. So I was sent home, as this is my first baby & i was 36w 2d at the time. I know am having some slight cramping like little quick dull stabbing pain near ovaries & diarrhea (sorry if tmi) the past day or 2. Is this the start of labor that could go on for a while (like days or weeks?) or is this just part of 3rd trimester? Im now 36w 4d & my next appointment with my dr is Wednesday the 20th. If this continues, do I call the dr. I just hate to waste anyone’s time. I wanna be sure next time I go into labor & delivery I’m actually in labor. Any advice is appreciated this is my first baby so I’m clueless of the process!😅💙