Only water and lemon juice? No BS and no maple syrup? You must have used up a lot of your alkaline reserves. (?)But I can still imagine it to be healing.
If you were to do it with the BS molasses, I think you might find it really do-able, and quite alkalizing -- or at least, moving you quite a ways in that direction; it's been helpful to me to undo the *habit* of food (and I don't have very bad habits that way, eating an almost pure vegan with a lot of raw food diet)
For me, the Master-Cleanse has been good for showing me how much food we eat, and how much better it feels to eat less, and feel lighter. It's also sensitized me more to balancing my life- toward it being more alkaline, in all ways.