Thanks for writing in to Healthcare Magic!
You might be having panic attacks but it is also possible that you are having intermittent cardiac arrhythmias of fast heart rate
like atrial flutter
, paroxysmal supraventricular tachycardias or some such sort of problem.
Still another rare chance is to have Pheochromocytoma
which produces abnormal amounts of hormones and cause arrhythmias and BP changes.
I would like you to get examined by a physician, get a holter test to detect the episodes of arrhythmia along with other battery of tests.
If you have any further query please let me know I would try to answer it for you.
Wish you a great health!