I have done it several times where I felt bad after doing the flush and I re did the flush 4 days later and I felt a bit better, but you will get better, but you have to continue doing it until your stone free, its the only way.
I'm still in the journey to remove all of my stones, I still get attacks and discomfort, but I doing better, of course watching what I eat and what time I eat.
For the discomfort and pain, I highly recommend:
mint or peppermint tea
castor oil packs
go on a liquid diet
I would highly recommend on de-congesting your liver.
Let me know how your flush went and how you been afterwards.