I have been on it for 9 months now for exactly the reason you stated and because nothing else would get my lupus under control. The first few weeks were difficult with the nausea and photo-sensitivity, but i'm prone to these to begin with, so this may not bother you. Also, there are the pills and the shots. I got the chills and felt really bad the first full day the first few months, but it does'nt really bother me so much now.
It does cause me to bruise more easily and scratches and cuts to heal more slowly. If you get a sinus or bronchial infection it will take twice as long to get over it. So you have to rest and take vitamins and read up on the methotrexate info they give you to be knowledgable. Don't be afraid, be informed. It definitedly has helped me.
Mia