I recently went up from 187.5 mg of Effexor XR to 225 mg. I took my first 225 dose 9 days ago, and yesterday I began feeling very overheated and weak at work. Today I feel the same, but also with a headache. Is it possible that this is a result of the increase in my Effexor dose, or has it been too long since the increase for it to have caused this?