What were your signs of going into preterm labor ??

I’m currently 27 weeks 5 days, was just given the news Thursday that baby is a lot smaller than what they want.... so they have me going to another ultrasound to see if baby grows any more in three weeks... TMI but yesterday I had diarrhea and still a bit this morning! I’ve started feeling a bit off today and now feel like baby is about to fall right out of my vagina... or my waters gonna burst (basically just a lot of pressure very low in my vagina ) no contractions though, baby is moving still , and no bleeding but the pressure just started about an hour or so ago and idk if it’s normal or if I should maybe give my dr a call... thank you if you’ve made it this far!!! what were the signs of preterm labor for you ladies?