Hi,
You may have Interstitial Cystitis (IC). It is an inflammatory disorder of the bladder that causes pain, frequency and the constant urge to void. Your frequency and pressure sensation are common complaints. The redness and pain at the vaginal opening may have just been a separate vaginal yeast infection. The urinalysis of IC patients is negative for infection but you do need a documented negative culture during symptoms to make the diagnosis. It is true that your primary care doctor will not be helpful in evaluating and treating IC except to rule out other causes of your symptoms. You need to be seen by a Urologist or Urogynecologist who specializes in pelvic pain for an evaluation and to rule out other causes of your symptoms. Eventually you will need a cystoscopy and hydodistention to make the diagnosis. Avoid cranberry juice. It's acidic which is good for UTI prevention but makes IC symptoms worse. Go to ichelp.org for further info. Good Luck.
The only bacteria that they test for in the doctor's office is E. Coli. My urine tests usually always come back negative although I have symptoms (pain, pressure, frequency). Ask your doctor to culture the urine sample in order to determine what type of bacteria you actually have and how to treat it. They usually will not culture a test that comes back negative in the office. Also I have found that cranberry juice makes my symptoms worse. It is the sugar in the juice, even if it says 100% juice, there is still natural sugar in it. One key thing with bladder issues is to stay away from all sugar. It's very hard for me, but it helps. That includes all sodas and coffee. Ask your doctor if it could be a yeast infection as well. My doctor told me that the symptoms can mimic a bladder infection sometimes. I hope some of this info helps you. I struggle with bladder issues too and know how miserable it can be. Best wishes.
In my opinion i would go to urologist. See if they can do a cystoscopy to rule out an IC. It seems that you have had previous problems with your bladder, so I would bypass primary unless you need a referal. Your primary dr. can only do a urine test and the urine test do not show an IC, at least it did not in my case. My reason for being sent to a urologist was due to frequent urination.