Problems with switching to Methotrexate

I'm new here, so I'll give my requisite summary and make it brief:

I am 18 years old, diagnosed with Crohns Disease in August 2006, although I've probably had it for a few years beforehand. I'm on remicade, and as a consequence I was on Imuran until about two weeks ago when I switched to the weekly injection-based methotrexate. After my 2nd injection, I started having delibitating intense traveling joint pain. My knees, my ankles, toes, wrists, fingers, thumbs, elbows -- when I moved it, it hurt. It never stays in the same place, and completely destroys my ability to run, walk, or lift anything heavier than a book -- sometimes not even.
Oh yeah -- and my tongue feels like a rake went over it.
This is unusual for me. I don't usually encounter any serious pain. I have my occassional attack every once in a blue moon, but this is the first time that the joint pain has gotten out of control completely. Advice would be much appreciated.

I made the change from 6-mp to methotrexate injections about 6 months ago.  The first few injections were really similar for me as they have been for you.  My Rheumy upped my folic acid and that really helped with a lot of the symptoms.  Make sure that they are doing bloodwork on your liver because both remicade and methotrexate can really effect it.  I had to be taken off of both this past week due to elevated liver and pancreatic levels.