I've been dealing with similar problems for years. My current urologist is reluctant to make a formal diagnosis, but we're proceeding on the assumption that I have interstitial cystitis.
My symptoms include bladder and urethral pain, painful urgency, and daytime incontinence. I've learned to avoid citrus, cranberries, and too much coffee (although I've not seen a difference between no coffee and one or two cups, so I usually can at least get my morning jolt). I've been told a variety of things by different doctors, from my current doc thinking it's probably IC but not wanting to commit, to another doctor telling me that it was prostatitis because "men can't get IC."
It's been a long and often frustrating journey. I've had incontinence during flares going back ten years (I'm 50ish now), which has worsened in the past year to the point that accidents range from once a week to several times a day, and close calls are pretty much a daily thing. I've worn diapers during the day on and off for the last decade, usually just for a few weeks when things were acting up, but every day since last October since I can't seem to get the current flare to quiet down. During the last time months I've gone as long as two weeks without an accident, to the point I was almost ready to quit wearing diapers for a while, but mostly I'll have four or five dry days, followed by several wet days. A lot depends on what I'm doing that day and whether I can sit down and breathe deeply through a bout of bladder spasms, then get to the bathroom promptly afterwards - if so it's usually just a close call, but if I'm not near a bathroom or can't sure and relax it'll turn into an accident.
I've been getting Botox three times a year and hydrodistension once a year, and while they've helped most times, over there past year and a half they've not done as well. I had to start doing intermittent self-catheterization after the first round of Botox back in 2013, and I've never been able to quit having to cath at least a couple of times a day, but my suspicion is that I was having partial retention even before the Botox, so I perhaps should have been cathing since before I ever had Botox. It's no big deal - if that were all I had to deal with, I wouldn't care. It's frustrating to have to both wear a diaper for all the urine that won't stay in my bladder, and self cath for all the urine that won't come out.
It's at a point now that I've brought up the idea of doing a urinary diversion and urostomy so I don't have to deal with it anymore. My doc wasnt very receptive to the idea because I'd need a urostomy bag, and bladder removal sometimes doesn't solve bladder pain issues. It's all ongoing discussion, though - I feel like wearing a urostomy bag is probably less disruptive than wearing a diaper.
My experience may not be all that reassuring. It's important to remember, though, that everyone is different, and my experience may not reflect what yours will be. I also have other medical problems that complicate my situation, and it's impossible to sort out what's due to what. I've had ulcerative colitis for 32 years, and primary accessing cholangitis for nearly as long (officially diagnosed 20 years ago, but evident in blood tests as long as 28 years ago), so I'm anticipating losing my colon later this year and begging a liver transplant in the next 2-5 years. You probably don't have that going on, so your experience may be much better than mine.
I'm sorry you're having to deal with this. It's a horrible diagnosis to get, and having to start dealing with incontinence and chronic pain is not fun for anybody. I hope you and your doctor can find treatments that work to get it under control! It's not an automatic sentence of a life of pain, incontinence and adult diapers, but chances are it's something you'll at a minimum have to deal with flares from time to time.
