Sour stomach before labour

Just wondering how accurate google is. How many women who have had babies had a sour stomach, diarrhea, nausea with or without vomitting no fever before labor started. Since last night I've been having BH with back pain and today cant shake this sour stomach with sharper period like cramps, nausea and lose bowels. I feel like crap. And urinating like every 15 minutes. No UTI symptoms. I'm 35+5 and have been in hospital 4 times the month of March for preterm contractions.