I, personally, would give it a couple more weeks, at least, before adding any more Cytomel (stay at 12.5 mcg total) It is fast-acting, but even if it does bring your FT3 up rather quickly, you are going to continue having symptoms for a while until your body heals. Are you still taking 75 mcg Synthroid, split. or are you just taking 37.5, altogether?