Self doubt

Hi there
I’m finding my job very hard at the moment because I’m feeling anxious and filled with self doubt. It slows me down and makes me less efficient. Also I feel dread before I go to work. It’s exhausting.
I think my thought is I don’t know what to do, I think that and I feel panicky and my actions are slower and erratic and my result is I still don’t know what to do.
Now I write this it makes sense i should practice the thought that i do know what to do. (Because I do)
I thought there was something wrong with me, but is it really just that I’m having an unhelpful thought?
These thoughts are just so automatic I think they are like an illness.
So I guess I just keep practicing the new thoughts and I’ll start to feel better?