a few weeks ago i felt a sharp scraping pain below my naval.

a few weeks ago i felt a sharp scraping pain below my naval.it only lasted a few seconds.later symptoms followed,urinary frequency,a blood speck or two in urine from time to time.NO burning urination though.the day my doctor checked my urine i started my period and there was too much menstual blood to tell if there was any blood coming from my urinary tract.she found no bacteria.but,she put me on 5 days of bactrim and a couple days of pyridium.my last dose was today.my backache is gone,but i still feel the need to urinate often.i've been drinking 2 quarts of water a day to flush out the bladder,but this is only adding to my frequency,which is driving me nuts!i pee and feel like i need to turn around and try again,which i know i can't when i just went.i've had bladder infections before or it felt like one and sometimes they can't find infection.i always get over the urinary tract infection symptoms but am left with this overactive bladder feeling.after a few months it too goes away.can a uti leave a person with temporary overactive bladder?my doctor wants me to get a complete urinaysis done at a lab.what all will they check for?what type of disorder?

Since your symptoms came on suddenly it does sound like a urinary tract infection. You need to see your doctor and get a complete urinalysis with a urine culture.