At this point, I honestly think you would be doing her a favor by telling her mother. I know that's not an easy thing to do, but that level of pain is how our body tells us that something is very wrong. A little bit of cramping or mild pain along with abnormal bleeding is often reason enough to go to a doctor, but that much pain along with bleeding when she's not sexual active is serious. ANY time you're in so much pain that you can't function - unless you already know what's going on and are being treated for it or something - you should be going to the ER. Even if your girlfriend gets mad at you for it, either you or her needs to realize the severity of the situation, get over the fear, and get her to a doctor.