I wish we had a lot more detail..like dosage, history, stim usage, anti e usage, bf %, bp rate, resting heart rate, diet, time of day you workout, etc etc
not asking for all of it but the more info you give the better advice you will get.
could be a lot of things and most likely is a mix of things
all i can really say is good luck and i hope you can get a handle on this.