Hi there I am going the doctors tomorrow about this because i think it s best but because my appoinment is 20 hours away I just want some reassurance. I am 22 female and overweight (by4 or 5 stone). I am also suffering from some anxiety symptoms . I have a borderline underactive thyroid and am on 50mg a day thyroxine. For a while now I have been having heart palpitations (or at least i think thats what its called) where my heart feels like it stops beating for a sec, I panic and then a moment later it flutters. This makes me panic and feel funny but is over in a moment :s I have been noticing this more and more recently, but over the last couple of days I feel like there is a weird sensation in my chest nd that my heart is racing. this is especially true when I exercise or am worried. This doesnt sound really bad does it because I am really scared now!