Right and Left Flank Pain

Hi there, I'm 16 and no one can seem to figure out what's wrong with me.

About 4 weeks ago, I started having really bad abdominal pain (mainly my right flank, in between my ribs and hip). I also occasionally have it on my left side as well, but not nearly as often or severe. It feels like there is a lot of pressure on my organs and it's worse when I sit down and when I stand up suddenly.I went to a general physician and my urine came back positive for WBC. I was having a major operation the next day, so we got a CT scan just in case. It came back negative for kidney stones. I went back the next week and they took blood and urine samples again. The blood test showed that I had high glucose levels (because I had eaten within the past 4 hours) yet my kidneys were leaking ketones. The doctor put me on an antibiotic and gave me a pain reliever but my symptoms persisted. Then I started feeling fatigued and just overall crappy.I have been drinking a ton of water, but I have been urinating less frequently. So I went back a third time. This time, they tested for bacterial vaginosis, and it came back positive, but I'm nearly certain that this is not what's causing my pain, especially since I've probably had that infection for a while (being 16 and not sexually active, I don't normally have too many vaginal problems). I'm just in a ton of pain and want this to go away! If these antibiotics that I'm on now (round 4!) don't work within a week, I'm going to get an ultrasound from a specialist. Any ideas of what this could be? Thank you!