one you might have ulcer your gas in your tummy thats wont let the air come out,two,you might have diebete 1ur 2 when your sugar is low you start to sweat really bad check those thing out with your doctor
I have exactly the same sypmtoms and I've been told is related to begining of diabetes type 2 and posible ulcer where you can manage it with diet, for me its when I don't eat regular meals for a day or two or if I skip a meal so at night when the bile should be doing its job of digestion at night, I can literally feel the burning sensation in my stomach that wakes me up and I get diarrhea like and end up throwing up at the same time,it then whe your blood sugar is too low and even your blood pressure drops that why you feel like fainting, also that happens to me when I eat a lot os spice or deepfried food STAY AWAY FROM THIS! Eat regular meals without skipping them, and. Ut down on sodas too much sugar and too much acids going on for your stomach, specially overnight so far I still get it every now and then but it bc of my negligence of diet. I hope you get to feeling better.
Insulino depend DIabetes (type 1) would be my guess, does carbohydrates intake helps? Try to take 15 to 40 grams of carbs when you feel that way, 10 minutes later if you feel better, my guess is you need to see a doctor of the hormones I dont know the real name in english ("endocrinologue" in french).
Hope this helps.