Possible signs of preterm labor?

Kelsey • Baby Girl #1 was born 10/5/17 Baby Girl #2 was born 2/15/19 😊
I have my next appt Wednesday and plan on talking to my doctor about this, but wanted to get insight here too!
Baby is head down and sitting really low in my pelvis (my u/s Friday showed this). I've also felt kicks very low in my pelvis now instead of up higher like they were for weeks.
Blood pressure has been normal. I've had loose stools the past 5ish days though. TMI, sometimes it's diarrhea and sometimes it's just really soft.
I'll be 30 weeks Wednesday. Anyone else having diarrhea and has baby sitting super low? I'm nervous this could mean I won't make it full term. Any advice ladies?