Hi [...] -
It is more than likely what other people are saying, that it's a negative effect of the withdrawal. I've heard of this before. You can definitely have inflammation without the bacteria.
But, I figured I'd add my advice... I am somewhat of an expert on bladder discomfort/frequent urination (ha) - I've got Pelvic Floor Dysfunction and (potentially) a bladder condition called Interstitial Cystitis... I'm not trying to tell you that you have these things, I just wanted to share what I do when I have flare ups, as my condition would be described as chronic inflammation without infection.
(1) Take a hot bath, fill the tub up to your waist and sit for at least 15 minutes. If you don't have a bath tub, take a hot compress to your lower tummy and lie down with it. Breathing through your stomach instead of your chest helps to relax any tense muscles down there (picture your belly filling up like a balloon)
(2) Avoid diuretics and acidic foods such as alcohol, caffeine, lemons, tomatoes, vinegar, spices, etc. I'm sure you would not be as sensitive as me but it is still a fact that these things can irritate the bladder/cause it to spasm more. Also, if you know that you don't have infection, don't go chugging cranberry juice, as this is also acidic and sugary.
(3) Do NOT let yourself pee every time you think you have to go (if frequent urination is a problem for you) - this could just be your bladder spasming and urinating too many times in the day will just worsen the inflammation. I set times for myself, I am only allowed to pee once ever 2 hours, no matter what I'm feeling.
(4) Avoid constipation if possible. Straining can cause inflammation to a sensitive bladder
(5) Drink aloe vera juice. This is like natures tylenol. It helps reduce inflamation and helps coat the bladder walls to protect it from acidic damage. You can same this same property in other herbal supplements such as marshmallow root
That's just a few things. I have about a million home remedies for this haha so I'm sure I will think of more.
Good luck