Hi, Sunic, and welcome! I had urinary problems (frequency & urgency) before dx and still have them 10+ years later, to a lesser degree but still there.
Here are some things I've tried.
1. If it's really nasty, my GP tests for a UTI or stones. (I hardly ever have UTI's, but I did have tiny stones once, which led to a complete urinary blockage. You'd know if that happens: pass blood, then can't pass anything, extreme pain, and violent non-stop vomiting.)
2. Before my lupus dx, I saw several urologists. Both considered testing for INTERSTITIAL CYSTITIS. But both decided not to test, because it's a knock-out test & they thought my #1 problem was something else.
3. I reported the problem to my rheumatologist when i was first dx'ed. He said "lupus cystitis" is possible but gave me no specific advice.
4. So I tried identifying foods/drinks that irritate, using lists available for Interstitial Cystitis as a starting point. Sure enough, caffeine, acid foods (like salad dressings), certain spices, carbonation, and alcohol (certain wines, especially) do annoy my bladder---but much more when I'm iffy overall. I actually can get away with those things at times, but at other times, no.
5. Good foods/drink? Drinking more water helps me some. I sometimes pop a few anti-acids to try to neutralize my urine.
6. Age? Well, that's not in my favor! I think post-menopausal women (I am) can have urinary issues simply due to age.
What has your doctor recommended? If "simple" UTI's aren't the cause, have you seen a urologist?
I hope this helps a bit, as I sure can identify with you on this. And I hope others chip in (we can't be alone in this?!), and that you post more soon. Best wishes, sincerely, Vee