New job. Brilliant new job, but my anxiety has exploded. I'm terrified of making a mistake (of course I have!), not being good enough, getting sacked. Overwhelming anxiety. Some days I am physically shaking as I walk in. I'm not sleeping (2:45am I woke up this morning). It's my day off and I am sitting here worrying. I didn't apply for the job, they wanted and went out and got me (a huge compliment). But I feel awful. What can I do?