Help. New to working

Tay
I've just finished school and I've scored myself a job in a phone repair place in admin. It's full time and I've just finished 3 days. I'm so scared that I'll never get used to it. In my lunch break I just cried and had to pull myself together as soon as possible. I did it but I feel so awful. How long does that last :/ I hate being out the front. Phone calls are not too bad though.