just a thought, when I had to cut out my sugars - I went thru a "sugar" withdrawal - lethargy, irritability, even sleepiness until my body adapted to not having the sugar in my system. Granted - my insulin is out of balance - or was - so I don't know how much that contributed. Is it possible this is a "diet change" issue? Course the other thing with all our bodies - it could be a combination of Several things but we can only describe how we feel at that time which makes it hard for the drs to tell.
And Amen to the peri syptoms but the "normal" blood test! Thank the holies I found a dr this year Finally who listened to ME and had some faith and didn't just go on "test results"!