It could be that you are sensitive to something in any one of your vitamins. There are a variety of binders and bulking agents in vitamins. I doubt it has to do with an overdose situation.

This also could just be a coincidence.

If you will list the vitamins including the brands, I can look into the label ingredients and see if any are common allergens.

I have the same ups and downs day to day and have tried to find a connection to my meds, vitamins and any other variables. I could find no correlation.