I have an idea. You report tiredness and poor digestion. it seems possible you may be low in some nutrients becasue of the poor digestion. Maybe when you take certain supplements you need, the enzymes that use them increase making you feel better but the cofactors needed are rapidly depleted.
does this make sense ?
When I went on the current diet I'm on, I was dead tired. I did an analysis on an excel spreadsheet and was shocked to find I wasnt' getting enough magneium, potassium, b vitamins etc etc. All because of hte diet. maybe this is an issue for you too