I Am Taking 250mg Of This Medicine For A Bladder

I am taking 250mg of this medicine for a bladder infection. This is the sixth day and I have three pills left. I am experiencing severe lower back pain. It is extremely difficult to get out of bed at night to go to the bathroom. I am dizzy and my balance is impaired. I am not going to finish the three pills that I have left. I realize that an antibiotic is supposed to be finished, but I can not tolerate the side effects. Do you have any suggestions? Thank you.