What Causes Painful Gas Bloating And Soreness In Stomach With Diarrhea?

Hello. For the last day and a half, I've been suffering from what feels like really painful gas bloating in my stomach accompanied by diarrhea. There's no blood in my stool, but it is really green. My stomach is sore to the touch, and I'm experiencing pain/discomfort no matter whether I'm laying or standing. I went to the ER yesterday, and they sent me away with "undiagnosed stomach pain" with a prescription for stool softener. The ER did an xray on my stomach and a rectal exam, and said they didn't see anything in either one. They tested my urine, and didn't find any infection. He did say my white blood cell count was a little elevated, but that could be because of the pain I'm in.

Have you heard of any situation like this? Any suggestions would be greatly appreciated. The pain is making it very hard for me to function at work