How do you know the difference between (TMI)

How do you know the difference between Braxton Hicks, real contractions, and stomach ache. I’m 28 weeks and have been having pain in my stomach for s couple weeks now, usually on the front side and top. It comes and goes but is irregular.

Well last night I started having uncontrollable diarrhea (tmi, sorry) that is yellowish-orange, and terrible stomach cramps. I got up 4 times during the night to go #2 and have had diarrhea probably 4-5 times this morning with terrible stomach pain. I’ve also been throwing up bile and water. I haven’t tried to eat but everything I drink comes right back up (or out) and I caught a cramp so bad earlier that I literally almost fell in the floor. It was my whole stomach and back and literally brought tears. I called my mother in law to come get the kids so I could go back to bed but idk if I should read more into this. Is it just a stomach bug, something I ate yesterday? Or is this pain a sign I should go to the local ER and at least get fluids. I think I would be ok to drive but if I catch a cramp while driving Idk what would happen.

Ughhhh