Hi Irina,
It does sound like you are depending upon the pills beyond what they were prescribed for. Have you talked to your dr about how to get off the vicodens? Also, have you talked to your dr or to a specialist about how to deal with the cystitis and the pain that is involved? Maybe there is some kind of treatment or surgery that could be done to relieve the pain.
You can get through the withdrawls and there is definitely hope for life without the drugs. Keep reading and posting.