Hi, !
While it is normal to experience some pretty strong side effects on methotrexate, I would definitely contact your doctor and discuss what you are dealing with, if you haven't done so already. That is a LOT of weight to lose in a month and if the diarrhea is affecting your ability to go about your day, that's something to tell your doctor. Fatigue and weakness can also occur, but again, the severity of your symptoms is a bit concerning. Also, if you feel like methotrexate is not a good fit for you, you have the right to tell your doctor you would like to discontinue taking it.
Gentle Hugs, Erin, Team Member.