Many years ago, I had a class on the balloon pump, and was reassured that I would have 2-3 shifts of hands-on orientation before I would be 'allowed' to do this on my own.
THE NEXT NIGHT, I came into work and was the only in-house RN in the unit. Yup, you guessed it, they could not assign the balloon pump patient to an agency nurse. Oh, and by the way, I was in charge, too!!! Spent the entire night with my heart racing, scared to death.
I survived, and the patient made it through the night.
You will be fine.