Hi.. Definitely the crampy pain in pregnancy can be similar to the ones as seen in ovulation or menstruation.. However you may have to consider the possibility of urinary colicky pain that can occur due to urinary tract infection which could also have been secondarily to the unprotected sexual intercourse.. Since you have taken plan B and the fact that there was no ejaculation, it may be due to the later, then pregnancy alone.. So drink plenty of water and see a doctor if the symptoms have been severe and persisting..