Attack of the Scary Anxiety

I've spend many hours laying on the couch scared of absolutely nothing. I feel like Monk. For no reason at all, I feel frightened. My heart speeds up. I can feel it pounding. I feel hot and start to perspire until I shake and feel lightheaded. I wonder if I'm having a heart attack. I know my heart is fine and there is nothing around me causing fear. I lay on the sofa, place my sweaty palms on my stomach, take deep breaths and watch my stomach expand. I blow out through my mouth thinking "there is nothing to fear. Slow down. You're fine." After a few minutes, I begin to relax, my breathing slows, and the heat dissipates. My heart rate slows but I'm still so light headed I dare not get up. These panic attacks occured over the past two weeks. Just at the same time I restarted taking Prozac.