Interstitial cystitis alone Willow is enough to make me cry for you! The constant pain, no agony, is enough to make one go insane and as you say be "ready for the scrap heap". I have this as well and I rarely like to talk about it since it is rather personal and it is pretty difficult for others to even comprehend how much constant discomfort and pain is involved.
The triggers, I agree, I use fragrance free everything but I find temperature is my trigger more so. I cannot get chilled in the least. Kicker being...living in the Arctic circle!!! Yeah, the irony is not lost on me, lol. I bundle up so well...crazy good. I take baths just to avoid any sort of chills, I employ heating pads religiously (applying to womanly areas) to stem off the pain. I also take high doses of Vitamin C, crazy high doses up to 10,000 a day. Anything unused flushes out of the body so it is kind of a waste but I have been having this issue since I was 4 years old but back then they didn't have a name for it. So, I saw a naturopath and I was at 4 malnourished and so sickly because of it and sulfa drugs didn't work, the doctors had no idea what to do for me, they just sent me home, malnourished and not eating. The naturopath gave me kindervital and high doses vital c, juniper berry and strict orders to NOT drink cranberry juice, not eat or drink anything citric, no tomatoes and nothing spicy. If I stick to this I am generally ok. I always have pain but it is manageable.
Willow, my heart goes out to you...hugs