What Causes Headache And Night Sweats After Changing To Estradot From Premarin?

Hi there:I was taking .31 Premarin since August 2013 then switched to Estradot 5 weeks ago to avoid the medication passing through my liver. I don t feel as good ... night sweats, headaches, foggy thinking and wakeful sleep. Is there a reason for this? Should I switch back to Premarin as I had no side effects with this. I m 61, was prescribed HRT because of Adrenal Fatigue, have had a hysterectomy with one ovary remaining at age 48 ... otherwise very healthy. Thank you.