Can prednisone make you tired? i'm supposed to be taking that and valtrex for a week. i'm out of it all day long. it hits me like a ton of bricks.

Yes. it can: Prednisone suppresses hypothalamus-pituitary-adrenal axis and decreases secretion of cortisol and aldosterone from the cortex section of the adrenal gland . That means low blood sugar and massing up your blood sugar , blood volume and bp. This can be corrected with mineralocorticoid and glucocorticoid medications. See an endocrinologist.