Hey there! Sorry for the late reply..🙂 Your situation is pretty awkward, but honestly, you’ve handled it well so far. I’ve met women who went as far as getting a hysterectomy because of this, and let me tell you, nothing actually worked better. Anyway, I heard this wild theory about it. Basically, your body isn't metabolizing certain substances the way it's supposed to. These things build up in your system, irritating your nerves, which then registers as bladder pain, nausea, or that urge to vomit. For some ladies, it feels just like PMS. The stuff bothering you is called biogenic amines. The most famous one is histamine. The catch is that you have to avoid spicy or heavy foods: pizza, salami, deli sandwiches with red meat, prosciutto, onions, red wine, pepper, kale, leeks, etc., etc., etc..
Treatment: Forget about NSAIDs.. This isn't PMS. You need to take H1 and H2 antagonists. H1: H1 : rinolan, Synopen, Claritin. H2: good old Peptoran.. But if you don't hold back on those foods I mentioned above, none of it will matter..
And obviously, before you decide on any of this, make sure you consult with your chosen doctor or pharmacist.
P.S. You aren't crazy, I know how nasty this thing is...