What Could Cause Fluctuation In Thyroid Levels After Changing Medicine Dosage?

Been on various thyroid medssince I was17. Im now61.anyway been on armour 90 for 4yrs n havebeen stable. Last blood test om 4/08/2014 showed I needed an increase, I have report in other room for actual #s. Dr increased from 90 to 120. Could tell right away that was tooo much. After 3 days on 120 I changed to 105 forbout 3 more days. Still felt awful w typical side effects, racing heart, pluse 120 resting, sweaty, hot etc. I decide to just cutback to 90 which was about 2 1/2 wks ago. Dr had also changed 2 other meds so I went back on both originals, each 1 wk apart so that I could tell if either was the culprit. Still experiencing same side effects Went into see him yesterday &toldhim it felt like over medicated thyroid. He did blood work which I just received. TSH=0.04 T4, FREE=1.3 T3, FREE=5.6 he said stop all armour for 2 wksthen start back up on 90 & come back in for retest after 4 wks of restart. Myquestion is , is it normal since I only took higher doses for 6 day & it s been almost 3wks later that my levels are so out of range? Im going to go get the original blood work to give u #s in april