Hi Sarah,
Thinking of you as the waiting game continues. As previously mentioned, thre are some really good sedatives that can be given to anxious people prior to MRI. I use to work in radiology, and many people are claustrophobic and anxious, and following the sedatives would often be so sure the MRI hadn't occured because they had no memory of the procedure, yet they had remained concious throughout. Just explain your fears when you book in, and there will be a protocol that they follow for you.
Good luck Sarah, you have already been through such a lot. I hope this will be nothing at all. Love Chris xx