Vaginal Atrophy can cause cystitis like symptons, or it could be the fillers in vagifem irritating the urethra but I'd have thought you would have had a reation before now if youve been using it for 8 weeks. Have you reduced the dosage after the initial loading dosage and perhaps need to up it again. The only way to rule out cystitis is to have your wee tested at the doctors.