Your concerns are perfectly valid and you seem to be well read. Prostatitis
could be infective or non infective and antibiotics will help only if it is infective. Interstitial cystitis
is a diagnosis of exclusion. One has to rule out all the causes of bladder inflammation
before considering interstitial cystitis. Exact cause for these diseases is not completely understood. However there are treatment available to improve the symptoms and quality of life. But one needs to be treated by a specialist and urologist
is best qualified in treating this.