Have IBS and now have stomach pain- help!!

I'm 21 and have had IBS for most of my life. But, it has always been somewhat manageable- if I avoid certain foods (high fat), I can usually avoid the pain. But recently, I started getting bad stomach pains. They're usually in the upper middle part of my stomach, but sometimes I feel them lower, in my side, and in my back. I've also had problems with diarrhea, but that seems to be better now. When my stomach gets bad, my back gets bad, and I get dizzy. My whole body just feels like crap. I also have lost my appetite. I feel full all of the time and usually have no desire to eat, so I've lost about 35 pounds. Certain foods make the pain worse, like raw veggies. I've felt like this for the past 4 months and no one (I've been to 3 doctors) has been able to figure it out!

I've had an upper GI endoscopy, gastric emptying test, and HB scan with cck. I've done a lot of blood tests to rule out Celiac, thyroid problems, and lots of other things. I've been tested for parasites and bacteria in my stool. Everything has come back normal, but I still feel horrible!

Anyone ever had similar symptoms? I don't know if my IBS has just gotten worse or if this is something new. It's so bad that I don't ever want to leave my house. Please help! Suggestions?