as a matter of fact these ups and downs are normal. Don't worry because in future you will have a lot more good days than bad days.
My first flush was in June 04 my last one in April 06. But the gain of strenghth (mentalwise and body wise) started around flush 11 (Feb 04).
Plus be sure that after having flushed out all stones there will come a time where you have to concentrate on eliminating toxins from the body. If the liver is stone free this organ will switch to a high speed detox mode and if you fail supporting te liver doing so there will be relapses.
I support the detox of my liver using activated charcoal on a weekly base. It does not interfere with my daily activities but each week I see the step by step even further improvements.
The point that you have reached the top of the mountain and can stop cleansing probably will never happen. This is as senseless as saying: Today I have brushed my teeth as thorougly as possible - they are clean and this should be sufficient for the rest of my life.
Concentrate on the positive changes (we human beings have a tndency to never feeling happy and nag around and to complain) this will help you more than asking me when my great breakthough happened. Cleansing is a process of constant breakthroughs - some are more spectacular other are less pronounced.