If your water didn't break, how did you know or why did you think you were in labor early?

I am getting SO anxious the closer I get to my due date (31 weeks now), especially with my history of fast labors and delivering my 2nd at 36 + 6. I've been having some pains in my stomach lately that have been uncomfortable, but not awful like contractions (my two previous births were unmedicated).

My next appointment isn't until 8/7, so I'm super worried about between now and then! I was supposed to go next Monday/Tuesday or Wednesday, but I had meetings I couldn't get out of.