Bad Move. SWF's are not laxative substitutes. They aren't meant to clear out blockages, just essentially rinse out residual leftovers. You should already be clear before a SWF.
Not knowing your exact condition, what I do, is after I've had a morning BM, either naturally or from a laxative the night before, I'd do an enema as a pre-rinse, then do a double SWF. By the late afternoon, I'd be passing virtually clear water. No need for a colonic.