I have heart palpitations and was shocked back into sinus rhythmn...

I have heart palpitations and was shocked back into sinus rhythmn via a cardio-vert procedure. I have been in regular rhythmn for over a year. However during this time my moods have become excessively black, my sleep has been irregular, and I can nod off at a moment's notice. During this time I have had lapses in short term memory and have suffered from bouts of bad judgement which I have never suffered from before in my life. My cardio suggests keeping me on these but I feel I must get off of the medication. I have been off for up to three days and have found that my outlook and vitality has improved greatly.