Hey there
i was disgnosed 2 years ago with ic. Although I have nothing like what you are having, I feel so bad for you. But I do understand the pain, to a certain degree.
I actually went to an eastern medicine doctor after about year, bc I just couldnt live with it. He gave me a few shiatsu treatments. I was fortunte to have a friend of the family who was an actual "healer" (kinda like mr. Meogee in karate kid)
well after a few sessions he new my bladder/body was very sick and understood. Within treatments he told me to take calcium. Actually coral calcium. I dunno if you take any vitmins, which i'm sur eyou have tried them all..... But I would really recomment trying the coral calcium (the one from okinawa, not hte cheapo ones they seel in drug stores)
it has helped my body so much. I can tell you more you are interested.
So anyway that was my 2cents