I guess I'll agree with the other two, don't know how long ago it was you last used, how long you did it had been so i really can't say. sometimes people crash and they do fall asleep when they are still speeding or their heart is racing it's happened to me before on many occasion. But you know your body the best, if something doesn't feel right than don't take a chance go to the hospital.
Pick up the phone and call 911.