I don't think I will be of much help, but This some times happens to me and I was told that it is from low blood pressure? or sugar. wow I can't remember which one now sorry. Anyway This may be TMI but it only happens to me when I have to go Potty and it will be loose stools and I feel very hot and sick almost like I could vomit. Now not every time I go to the bathroom (once a day) does this happen. I have noticed it happens every week give or take a few days. I have also noticed that it's on days that I did not eat breakfast right away. Eat as soon as you get up and graze through out the day (healthy snacks and meals) and see if that doesn't help :D Good luck
Based upon what you described, I'd say your situation is due to low blood pressure caused by vasovagal syncope. I see this too often as a RN.