Prednisone

Hello! I was prescribed a round of prednisone recently by my pm&r because my meloxicam stopped relieving my OA symptoms. He also ordered an upper and lower extremity emg, but I’ve had so much medical trauma in the past where even though something is obviously wrong, things don’t show up on tests so I did not take meloxicam or start the prednisone in the time leading up to my emgs. Those are past now and I’ve now been ordered an mri of basically my entire spine because of R arm and L leg weakness. My question is should I start the prednisone pack before I get my mri, or should I still continue to hold off on that and my meloxicam until after my mri? My emgs came back with slight irregularities, but my doctor believes an mri will show more information. I’m just so paranoid that I’m gonna do something that will hinder my test results causing me to not get a proper diagnosis, and then I will continue to be in pain forever. Is this an irrational fear, probably.