Sorry I didn't reply sooner.
It seems like I might of had an infection/virus in my system when I had the steroid injection, and the inject brought it out with a bang. A few weeks on and I now still have a really bad cough/cold and after my rheumy nurse has told me to stay off the MTX for a few weeks as she though it was stopping me from getting better. Also, my blood showed a pretty high white blood count and my CRP had rocketed up, so my GP wants me to have the bloods done again next week to see if me being of the MTX is helping me get better.