It can be frightening to get what we want. It is understandable to feel uneasy about something new; after a while it won't feel new any more.

You will not be wasting their time. If you could 'snap out of it' then you would have, because you haven't been enjoying being anxious.

When you go, let the therapist know how uneasy you feel. He/she will understand because I would guess that 99% of people who begin counselling feel uneasy/frightened by it. The therapist will help you say why you are there. It can be simply that you feel anxious a lot and you don't like that. And that it's interfering with being able to work.
They will help you understand it, and help you with the fears that you have.

It will be okay. You won't be expected to solve this on your own. The therapist is there to help you learn about yourself and how to help your life feel better. You won't be expected to "perform" or prove anything. A therapist doesn't judge you or try to make you feel bad or feel guilty. They are just there to help you as best they can. They are an ally. I hope you will give yourself the gift of the opportunity to try and see how it goes.