Hi. I wasn't aware that they treated fibromyalgia with methotrexate? I always assumed that if you respond to mtx, you DON'T have fibromyalgia and have an inflammatory arthritis instead. Maybe that's why your doctor put you on mtx? In any case, when I first started taking mtx, I also had some stomach issues. I had a lot of nausea and some lower GI cramping that occurred for just a few days after taking the weekly mtx. Gradually, it resolved completely and I have no issues with mtx at all. Are you sure your stomach problems are related to the mtx? I know that if they continue or are bothersome, you can be prescripted mtx in injectable form so it bypasses your stomach. Mtx has been a great drug for me so far.