Horrible back pain on both sides? Help?

For the past few weeks I started randomly getting back pain, lately it's been everyday. And it's getting really bad. The pain is located on both sides of my back it moves around a lot, but it's like above my hip area, mid back/waist, I guess. It's on my actual back, but it's also like my side area, by my hips and all. It's random and sometimes feels like very sharp stabbing pains, it sometimes makes me nauseous and feels like it could knock the wind out of me, other times it's just a dull aching pain. It's not fun AT ALL. My stomach is sometimes bothering me too when this happens. I also have everyday abdominal pain, but I don't know if that goes with it, I've had the abdominal pain everyday for a year and have been to several doctors and am finally able to see the GI soon. I also have severe anxiety and am a hypochondriac. So of course I'm considering the worst. My period is supposed to start soon and I have been constipated for the last few days (TMI I know..sorry...) but anyway. I'm worried it's my kidneys, but my parents are saying it's not. I'm begging them to take me to my doctor, but they think I'm fine...but when I'm crying in pain...I'm kind of not.. So what could this be? I'm terrified and SO sick of being in pain! :( Thank you.