Sounds like a classic panic/anxiety
attack. Although honestly a pulse rate of 124 is not too high. To put in perspective, when a 24 year old does a cardio work out, his/her pulse rate should be at about 155 bpm. So 124 is not enough to cause extreme duress on the heart. It does sound like an anxiety/panic attack
, so you might want to consult your Doctor about your options, especially if you have any more episodes.