@ysmina-- Cystitis or interstitial cystitis are other names for bladder inflammation. It basically means that you have a urinary tract infection. If you have cystitis, you will probably have pelvic pain, along with the urge to urinate frequently. Take your antibiotics and you will be fine.
I used to think that cystitis is due to me catching a cold. I've only had cystitis a few times in my life, but they've always occurred when I had a cold. So I thought that the cold was causing the frequent urge to urinate. My doctor said that however, bladder inflammation is most often due to bacteria.
There are actually many other causes of frequent urination. Diuretics (even coffee), medications and diabetes can cause this symptom as well.