That has happened to me quite often, I feel more or less OK when I take the first ES dose, less OK after the 2nd dose and all congested and bloated with pains in my upper abdom so don't take the OG. Often the next day I'll not eat but keep up the fluid intake then repeat the 2 ES Doses and usually can have the OG 2 hours later.
What seems to happen with me is that the upper intestine is inflammed and the food I've eaten passes thru slowly and is not cleared out by the time I start the ES. This slow down allows bacteria and yeasts to overgrow and produce the gas and bloating. Since ES only works in the large intestine I take herbal laxatives to help clear out the small intestine. Since the upper small intestine and bile system normally do not have microorganisms present - they have been killed off by strong stomach acids and bile - this may indicate you have these organisms where they should not be.
There are some medical tests to id these organisms. Using Hydrochloric acid drops or Betaine HCl with meals might help to kill off some organisms that have been forced back up into the stomach. I've used Clark's modified Lugol's Iodine, turmeric, cayenne, raw garlic, Candida herbs. It is more difficult to kill off microorganisms in the bile system.
The congestion in my small intestine is caused by autoimmune Celiac Disease, gluten sensitivity and intolerance and food allergies . A parasite Cleanse killed off some worms in my small intestine and bile system.