Bam,
Those machines are not maintained as they should be. I have had the same experience...and when I took my pulse manually, it was not as high as the readout!
You had a reaction to seeing that number, and that is why you panicked and couldn't breathe.
Always take your pulse manually...or have an employee help you if you are not sure how to do this.
I hope you are feeling better now, and this will not deter you from working out!
Exercise is a GREAT anxiety buster!!
Check back in soon, but you are going to be fine.;)
S.C.