Keep going and don't worry. Compare how you originally felt to where you are now. I saw pretty good improvement after the third, but I am now far better off after the fifth. My pain would also creep back in after I started eating again the evening following the flush.
Get your boyfriend to do a flush with you. Maybe it will calm some of his anxiety ;) Besides, a little pain under the ribs is nothing for an IC veteran. Poor doctors, who would have ever thought a pint/day of boiled broccoli broth would do more for my pelvic pain than their $450/month dosage of Elmiron.