The impact of flushes, emotional or physical, differ from person to person. One active flusher says she flushes while on business travel! That seems like a stretch to me, but it works for her.
I don't have much trouble with illness, sleep or the day after flushing. Others report that they do. The frequent trips to the bathroom the day after would make it hard to work.
In general, the better one preps for a flush, the easier the experience. Take the trouble to squeeze fresh ruby grapefruit juice -- especially this time of year. Mixed with good olive oil, it actually tastes good!