How do you know when you’re in labor?

This sounds like a stupid question, I know, but I’m 40 weeks pregnant today. Yesterday, my doctor did my third cervical sweep and I have been having cramping and contractions on and off ever since. Last night my contractions were coming for a few hours but they were irregular. They were uncomfortable but it wasn’t HORRIBLE pain, I could talk through them. They lasted about a minute each. I decided to wait it out and they eventually went away. This morning I have been cramping and I lost my mucous plug (no blood though). I started having the uncomfortable contractions again.

When will I know when it’s time to go to the hospital? My worst fear is showing up and being too far along to get an epidural! This happened to a friend of mine!! 🙈😳

I’m obviously a FTM and have no idea what to expect!