I've been suffering from the same symptoms off and on for three years, with the past year getting much worse. My weight loss has been significant. If you haven't mentioned this sx to your neuro, you should. I finally did, and she sent me to a gastroenterologist who did a study and found I had gastroparesis; a condition where the stomach doesn't empty properly. It can cause nausea, constipation, diarrhea, vomiting, etc. While the jury is still out on whether or not MS caused the gastroparesis, it seems as if it could. Its a permanent condition, though meds can help.