I never had die off like that. Major diahrea thats like water? Maybe thats the way your die off goes, but if it was me I would be stopping the GFSE and switching to an alternative anti fungal.
It sounds to me like you are having a bad reaction to it, if that's the only thing you are doing, and the watery stools cannot be attributed to anything else.
Die off is more like an inflamation of your normal symptoms, feeling tired and groggy, listless, brain fog, irritability, and the like. That sounds more like a fever.