What Is The Cause And Treatment For Bladder Infection?

I saw a Doctor on 1/12/15 for lower back pain, low grade fever, swollen neck lymph nodes and fatigue, who proceeded to take a sample for urinalysis. He informed me that my urine came back suggesting a bladder infection. I informed him that this is the 4th one that I have had that I did not know I had in 3 months when I came into the doctors office for other ailments (I had suspected flu or pneumonia due to body aches, fatigue & fever of 100.7). He prescribed me a higher antibiotic than I have been prescribed before and said that he believes I have a kidney infection, he also prescribed me tramadol for any pain that may occur although I try to stay away from strong pain medication. It has been 5 days since I have begun the antibiotic, and the pain in my lower back is increasing in intensity and duration, it is constantly throbbing in pain and even tender to the touch. I will feel a sudden sharp pain on my right side in my kidney area occasionally with no activity other than just sitting down. It hurts in my lower back and in my bladder area when I urinate, but not a burning sensation, only intense pressure.The pain in my lower back is becoming near unbearable, easily a 7/10 on a scale of pain that keeps me up at night and even wakes me up in the middle of the night. All I physically want to do is lay in my bed on a heating pad because of the uncomfortable sensation and pressure that I have in my kidney region. A few months prior I made a commitment to drink the recommended 8-10 glasses of water a day but in the past 2 months I have increased my intake to 12-14 glasses a day due to these problems that I am having. Is something more serious going on or do I need to wait until the antibiotic is completely done to see any results?