The same thing happened to me after a week on Oxypowder . The epsoms cannot stimulate a BM if there is nothing to be excreted. You're probably just "empty". The epsoms relax the bile ducts, the olive oil stimulates release of bile & the citrus makes your gallbladder contract, so as to push out the stones, bile & stuff. At least that's my understanding of it...
Yeah, do the flush. You don't want to have drunk those putrid epsoms for nothing, do you? :)