I need help figuring out what is wrong with me - I am a 19 year old female with no history of bladder infections or problems with urination. One evening I suddenly got pains in my lower back, legs and pelvic area -these symptoms came on within half an hour. They were not very severe although I did need to take some ibuprofen to get to sleep. The next day most of this pain has gone and has not really come back since, I could only feel slight pain in genital/pelvic area. I went to the doctor's this day and they took a urine sample, thinking that I had possibly developed a urinary infection. No infection was found but I was still given a 3 day course of antibiotics because of the lower abdominal pain and slight pressure on the left side. The day after this I noticed that I needed to go to the toilet a lot quicker than I usually would- I can normally wait 4 hours before feeling the need to go. I was drinking more water to get rid of a supposed infection so that may have increased the frequency. However, the antibiotics did not work. I still had to urinate soon after drinking anything and my bladder even hurt one morning. I was put on a different 7 day antibiotic 2 days ago by another doctor who said I will need to have blood tests to see what is irritating my bladder. I am drinking normal amounts and yet my bladder always feels full, even after I have gone to the toilet there is still slight pressure in my bladder. Today I can still feel the slight pressure and I also have a back pains and pains in my legs and thighs. At no point has it hurt to urinate- there is no blood in my urine either and I do not have constipation and only get it rarely.
What could have caused these symptoms to come on so quickly and out of the blue? I have no STD's, a healthy diet and I doubt that any anxiety or long-term disorder could have caused these symptoms literally overnight.