If you have some time during your vacation, you should catch up on some forums postings. They will give you the answers to your questions you have asked. :)
Read the FAQ's too. It's another great starting point to learning things about flushes.
one thing I have gleaned from reading posters questions and advice, is that it is best to wait a minimum of 2 weeks between flushes. This gives the liver/gallbladder time to replenish the bile reserves. The 'rush' you felt could be a reaction to the amount of magnesium you've taken in using the ES. I just read in some posts over in the 'ask shelley' forum, that the ES concoction can upset electrolytes and calcium levels, which can do that to you. Might even consider enema for the morning instead of another ES dose to get rid of the stones your liver/gallbladder may have released.
This is just my two cents from what I have learned by doing alot of reading on others results. Hope some of it is right! *grin* I'm sure I'll be corrected by those with more experience and knowledge if I am incorrect.