Little concerned

Okay so for warning this post is about gas and poop. For the past 3 days I've had major gas problems. I'm 27 weeks and my stomach was so full it was hard everywhere and then it hurt really bad. So I tried to relieve the pressure and nothing but fats came out. So I ate cause u know gotta feed the Lil one. Then tried again after wards. Successfully passed a bowel movement. But it was explosive diarrhea. Stomach felt way better afterwards. Fast forward to when I got home after work. Some gas and then again with the diarrhea. Next day same thing. Now here's where I'm concerned I Google diarrhea in the third trimester cause I'll be 28 weeks Monday and it said that's a sign for early labor. On the other hand it said the it could be a viral or bacteria infection. I just had a cervix check done on Wednesday and it's long and closed. But all the poop and gas started after I had the ultrasound done. My next doctors appointment and ultrasound isn't til the 30 and I'll be 29 weeks. I hope I'm not going into early labor cause in my last pregnancy I fully dilated to 10 cm and didn't know. I just thought I was having gas pains. 😕