Thanks for your query.Based on the facts that you have posted you have Interstitial Cystitis
and suffering from severe pain
To be honest there is no proven effective treatment for interstitial cystitis inspire of many research studies to find out the aetiology of IC.There are multiple trails of various drugs on this front and very difficult to predict the results of particular mode of treatment.in individual patient.Some of the modes of treatment.that are practised world wide are as follow.
1) Pain killers and anti depressants.
2) Bladder distension
3) Instillation of a drug like DMSO
in the bladder.
Consult qualified urologist
for evaluation and treatment.
Best luck and wish you speedy recovery.