If you have noticed it especially with dairy, you could have a lactose "intolerance".......certain medications can effect the guts' ability to break down complex compounds in food......

If you can cut dairy for 2 weeks and see how you feel......I also do not eat dairy, for similar reasons. I am also going through hormone disfunction which contributes to feeling awful. But dairy is a nasty.......try and also cut bread out, steam all vegetables lightly(no raw food...it can aggravate the gut which will make you feel tired and sad) and keep fruit to a minimum(sucrose can also effect the gut).......

Try it for 2 weeks and see how you go......

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