Cause: New diet?

I'm in so much pain right now. I've recently, within the past 2 weeks, became a vegetarian and I haven't eaten any meat. I've noticed that since starting this I've had diarrhea. But right now it's worse than usual. I had diarrhea and now my stomach is in excruciating pain. It's almost 3 am and I can't sleep and I don't know what to do. Is this all because of my new diet? How can I stop this and what can make the pain go away?