Anxiety Support Group
Anxiety is a physical condition marked by intense and persistent feelings of distress, fear, angst or dread. General anxiety caused by routine day-to-day stresses usually passes quickly and is experienced by almost everyone at one time or another. However, such feelings that linger over time and are very difficult to cope with, and which lack a clear cause, may indicate...

It can be frightening to start a new job but everyone has done it, and everyone has been freaked out. Even your boss, long ago. Do your best, expect to make mistakes and remember that's okay. I keep talking a new girl down at work: she tries too hard and expects to make no mistakes ever. LOL. Mistakes are a thing. We make 'em. It's okay.
Apologising for them and telling people you feel stupid for them will, if you don't overdo it, pretty much trigger a laugh and a caring 'don't worry' as we all remember the horrors of our youth. People are glad to know that you care, but don't expect perfection straight off.
And when you're young in a new role, you will pretty much get babied all through how to do every task. Take notes though. That's all I can say. Take notes when you are taught something. :)