You should definitely see someone about it, maybe even a regular doctor instead of a therapist. Do you think it's your heart, or more of a seizure type shake/jolt? Skipped heartbeats or arrhythmias can feel like a jolt, but they're usually not harmful.
What meds were you on? Could you possibly be going through a withdrawal period?
Sorry you're not feeling well, hope things get better! *hugs*