Premature labor

Hi everyone. I’m 33 weeks with baby #3. Not sure if it’s due to this being my 3rd but I just have a strong feeling I will be going into labor early. The way my body feels, the back aching allllllll the time. The way my tummy has dropped quite a bit. Just the way I feel. I’d say within the next 4 weeks...

Anyone here gone into labor early? How early? What were your experiences? And how long did your little one have to stay in the NICU?