Thanks for your answer. I had a glucose tollerance test some time ago and it was negative. My symptoms can last for at least two days and result with my hyperactive stage, so much longer than you'd expect for hypoglycemia I thought! I also didn't mention I can feel queazy then too.
Can you advise on how to investigate possible allergies and what I can do?
I will ask my GP to do another GTT. Nutritional imbalance sounds probable with my gut problems and dodgy brain function. I thought maybe nutritional deficiency but my GPs say that's not possible as I don't have the usual symptoms! I'll ask them again. This is a complicated problem!