Hi! I appreciate your concern for the delayed period. Non penetrative sex does not cause pregnancy however it depends upon the pre ejaculatory secretions. Since pre ejaculatory or pre cum secretion from the penis contains sufficient number of active and motile sperms, so if this secretion makes entry during the sexual act, the chances of the egg getting fertilized by the sperm are high and hence pregnancy. So, there are two possibilities of delayed period in your case, first is pregnancy which should be ruled out by urine pregnancy test the second may by due to stress or hormonal imbalance. Hope to have answered your query. Good luck.