I've been doing the injections weekly for about 8 months now. I find it easy to administer , you just do the jab under the skin , not into a vein or muscle. I put in my front love handles, haha , just in front and above my hip bone. Get the druggist to explain. I Googled .. I think it was ; "Methotrexate self injection" , and read about it and , I think, watched a demo video.
Same as you the pills weren't effective. Not all bodies absorb drugs in the same way. My rheummy said that you are lucky to get about 80% of the mtx using the pill form.
Good luck. It's easy.
The large number of us , and millions of insulin users wouldn't be doing it if the "hoar stories" had an ounce of fact to them.