There is some great advice in the comments above. I had a job where I felt like you even though I was experienced. The job was overwhelming because it was a new area for me and they only gave me 2 weeks of orientation. The physicians were very abusive and intimidating and everyone just put up with it. It was a relief when I had to quit for childcare issues, but I still waver at the lost opportunity to learn.
I suggest you apply some of the above advice and seek out help to improve things, but the more time you spend there the easier it will get. Maybe your manager will work with you and lighten your workload for a time period.