Lower Abdominal Pain

[Derpyshy]

For the last few months, I've been experiencing excruciating in my lower abdominal area. Mainly when I go to the bathroom, that radiates to my back sometimes. Which I've had kidney function tests, liver function, went to my gyno and she said that it wasn't my PCOS (obviously because my ovaries are down a bit lower). I've had a CT done recently to check for kidney stones, but there have been none. At the same time I've been unable to pee for a few days, and get  so sick to my stomach that I'm unable to eat. I've even went to the ER and they say that there's nothing wrong with me. I'm not sure what to do anymore. My doctor's without answers, I'm unable to eat half the time and don't know what to do. Any help would be appreciated. Even as I'm typing this I'm unable to sit up straight or sit up at all without awful pain.