Pre term labor? Please read and comment 😩

I'm 33+2. I feel silly asking this here as I'm a STM and assumed I would know when labor was coming. It was easy with my first, my water broke at 39 weeks so it wasn't a guessing game. 
This all started Saturday when I woke up and felt achy all over. I thought maybe I had the start of a virus but I only ever got achy with no other symptoms. Sunday, contractions began. I had 30 in 12 hours. Monday I had 52 in 12 hours and lost the largest chunk of my mucus plug thus far. Tuesday they continued and I was seen by my doctor. Cervix is closed but low. My water hasn't broken which they tested for just to be safe. Fetal fibronectin came back negative as well. 
Today was ok, just a handful through the morning and then an increase throughout the afternoon. Then came waves of nausea and (TMI) diarrhea but it was just once. Now, lower right back pain that radiates to my groin and hurts with each contraction. Normally a heating pad on low for about 10 minutes alleviated the back ache but it's not helping tonight. The contractions were 24 min apart, then 18, then 14 and now 9. 
Does this sound like my body is getting ready for labor? I have another check up tomorrow, I'm just so nervous our LO is trying to make his appearance early 😔
Thank you to anyone who read this and comments!