How can I learn to relaxing during this procedure?

My bone marrow biopsy was cancelled today and rescheduled for thursday. I was really nervous today as it was and now I have two more days to wait. I have had one before and it was really unpleasant, done only under local. I am normally good about things like this but now I feel sick, my hands are shaking and sweaty and I feel like I could cry at the drop of a hat. How can I get through the next two days and the op?