I don't know if it's exactly same thing but I have found after some stress effect on my stomach for at least a year, my stomach seems to struggle with certain foods, and any that caused this sort of issue, I have cut from my food shop so I don't experience it. I found I'd feel very sleepy and bloated, would take correct insulin for my food, then have a nap, then wake up very high. Stomach problems do cause energy level issues usually so I put the tiredness post meal due to that, but yeah, removing the foods has stopped the post-bloating highs. Hope you'll be okay. I've not had a diagnosis of anything for this issue. Stomach issues can be a diabetes complication but I'm not sure I'm experiencing that because I don't tick all the boxes for it... plus I had a very stressful time for at least a year and I don't think my stomach has been the same since regardless.
