16 and have Ulcerative Colitis...?

I just got diagnosed with UC about 2 months ago..since then my doctor has given me 3 remicade treatments. I just got my last one last Thursday and ive been on prednisone for awhile. Im weening myself off of it (currently taking 20 mg) and last thursday my doctor started me on Methotrexate. I take the shot once a week until we get my diarahea under control and then hes going to switch it over to the pill. Ive noticed that im REALLY shaky all the time...my legs are weak and shake when im standing. This isnt one of the side effects of Methotrexate or at least it doesnt say it is. Has anyone experienced this while taking Methotrexate? I dont know much about my disease. Im still getting use to having it and itll deff take time so any advice is very useful =]