Two Weeks Ago I Had A Cardioversion For My Atrial

Two weeks ago I had a cardioversion for my atrial fibrillation not being controlled with diltiazem I.V. My cardiologist doubled my flecanaide dose to 100 mg (or mcg) twice a day and added Diltiazem 180 mg/mcg once a day. My blood pressure fluctuates and at times during the day I am light-headed which makes me not feel well--somewhat like coming down with stomach flu. Should I get a second opinion from another cardiologist outside the group?