Bladder and kidney problems-possible interstitial cystitis

I have had constant urological problems for about 5 years now.  It started off with frequent bladder infections (every 2 weeks to every 2 months or so).  I was constantly told that it was post likely due to intercourse.  After about 4 years of being treated with antibiotics for bladder infections, I started getting severe back pain and was sent for a kidney ultrasound.  They found that my left ureter was squeezed by a blood vessel and that my kidney was not draining.  This was causing the back pain and I was told that it could be the cause of all the bladder infections.  I eventually had to undergoe pyleoplasty surgery to release my ureter from the blood vessel and now my left kidney is permanently stretched.  During this time; however, I discovered that out of nearly 30 times I was treated for bladder infections, there was NO BACTERIA in the culture. My doctor is now talking to me about interstitial cystitis.  I just wnated to know what you think of this...get a second opinion.  Along with frequent bladder attacks and pain, I urinate 15-20 times per day (roughly every 45 minutes), have nocturia, and have painful intercourse!!! PLEASE HELP!!!!  I am so tired of all this urology discomfort.  How can I minimize the attacks on my bladder and reduce urinary frequency??