The ICA has a great website
HERE
Tons of information and tips --It can be a little overwhelming though as far as neuro cog stuff goes though. I get the newsletter -- quarterly I think. Easier. and they have info packets you can send for -- easier for me to read off screen.
Have you been to a urologist ? Finding a good one near you to work with is important. I was dx'd back in the late 80's -- directly linked to alpha interferon injections. DMSO cocktail installations helped a bit. Not sure many docs use those any more -- there are better options. They are certainly worth seeing someone to find out what might help you. Make sure you find a IC savvy doc though ( the ICA support groups can help with that)
Mine was constant and unrelenting for years. Over the past few years, for reasons unknown, it has calmed down and I get flares a few times a year. The base symptoms are there but mild.
What helps me during flares :
Constant sipping of (filtered)water. It helps flush out the inflammation, it is also less painful to have something in there when you have the constant urge then to be empty, imho.
Phenazopyridine Hydrochloride ( brand names uristat, AZO) sold OTC will numb the inside of your bladder. Gives me some good relief for some of the symptoms.
ice pack on the lower pelvic region can help spasms. ( if you are in a cold climate, use a heat pack somewhere else -- ie shoulders) to counter act the cold effect on your whole system)
Stay away from foods that are high acid, carbonated, high potassium, caffeine, and spicy. In other words a bland diet.
Keep a journal of what you eat, how frequent you go, etc... can help you figure out triggers and good info to share with dr.
It's a horrible disease. Sorry you are suffering.
ETA: the suggestion of anti-histimines. It can help some people, others it can make worse. Just thought you should be prepared for that. Best .