Hi Everybody, Its been a long time since i have posted anything. I was having panic attacks for a long time. I got on Zoloft and saw a shrink, it helped. I got pregnant and had a baby and he is perfect

Today I went back to the gym to workout......its been almost a year and I was on the treadmill and I was very aware of my heartbeat and within seconds I was having a panic attack. The dizziness, the fast heartbeat, the sick to my stomach, cant catch my breath. I am so mad at myself for having one. It has been so long, I just cant get it out of my head that there is something wrong with my heart. I have no reason to believe that.....I just do. Does anyone else have this problem? I cant stop thinking there is something wrong with me. I know any minute I am going to have a heart attack or my heart will stop beating and I will die. HELP! Is my zoloft not working? Can it just stop working or did I put myself in this frenzy because of the heightened awareness of my heatbeat?