Don't know if you have gotten this taken care of yet, but the exact same thing has happened to me.
It honestly felt like a sharp knife was stabbing me over and over for hours on end. I finally gave up and went to the ER. They did a bunch of tests,ultrasounds thinking it was my gal bladder.
It ended up being Gastritis, which certain foods as well as gluten would trigger that inside my body. I had to take a few medications and get on really low carb diet for 2 weeks.
Now I know, and it hasn't come back, but that is because I have changed my whole style of eating.
Gallbladder pains are more in your lower back, and they say it will feel worse than childbirth. I have no children, but the pain I had, was absolutely killer.
Hope that you have gotten it checked out, it freaking sucks being in that much pain.
RE: Gallbladder
Ugh! Let us know what it ends up being, I am quite curious myself! Good luck lady! :)