The only time I have heard of folks having blockages is with either Crohns or diverticulitis. I can't believe that with a blockage like that, that they can't get you in sooner. I would go see your family doc in the meantime and see if they can't help you to get in sooner. Obstructions are nothing to mess with, you could perforate and have some serious problems. If you get that horrid pain again, I would go back to the ER, don't let it go.