Fast heartbeat symptoms and conditions

In January of 2008 I was diagnosed with Diabetes Type II, I was prescribed 500 mg of Metformin twice a day. After six weeks of therapy it was still ranging in the 200+, then the doctor added Actos 30mg and Lipitor 20 mg. One month after taking these, I started feeling dizzy, light headed. Then one day out of blue while driving to work, I had what I felt as a severe panic attack, fast heartbeat and sensation of near-fainting and a throbbing headache. At first I though it was just severe anxiety. I let the doctor know he just said it was stress related anxiety and referred me to see a therapist. Kept taking Actos and Lipitor and the episodes kept coming stronger and more frequently. To make a long story short, my children got concerned and looked up the medications I was on and looked up my symptoms on a website called ****** and discovered that I was not the only one having these same side effects. I have stopped taking the medications now for four days and my symptoms have stopped and starting to slowly feeling better.

Very fast heartbeat and very little sleep. I have been taking 500mg for 5 years this month.. I did not take one last night and had no problems with heartbeat. Could some one tell me how to stop taking Niaspan. Can you quit all at once.

Thank you very much