Most of us have probably looked at the lemonade drink with utter hate and loathing. However, we force it down sip by sip and try to concentrate on the good things we are doing for ourselves. Eventually the drink can become tolerable.
That detox headache you experienced can ruin the cleanse for a lot of people. If you can stay strong and work past the initial discomfort of detox, plus, for many, Sugar and caffeine withdrawal then The Master Cleanse becomes so much easier. However, if you do become too ill from severe detox to function, then stopping early may be a good idea. Only you can make that call though. Discomfort is part of detox, making yourself sick is not. If you must stop, then eat and cleansing diet for a few weeks or months, and try again.
By the way, if you think the drink with Maple Syrup is bad; then you will probably find the black strap molasses really disgusting-it was one of the nastiest things I ever put in my mouth.