How to get rid of negative/anxious voice in the head while doing something

This week I was happy to try for the first time to apply the “Monday Hour One” technique. I was (and I’m still) super enthusiastic to apply this method and get things done!
I also watched the “get things done video” it was really inspiring! I’m excited to tell myself that I’m becoming more productive.
On one hand I achieved a lot of things this week and I’m proud of it but on the other hand I didn’t succeed in respecting totally my calendar.
To be honest I succeeded in achieving 75% of what was written on it.

For some reasons, I didn’t plan precisely the time it took me to come back from meetings (I will take this into account for next week) I started some tasks with a delay but also I noticed that when it was related to applying job tasks it started to become much harder when it was planned.
It has been a long time since I have applied for jobs and it takes me a lot of time to write a cover letter (particularly in english) but also I think that I have too many thoughts while doing this.
I have thoughts like ” I’m not sure I want this” “I don’t know where to start” “Do I really want to work for a company”
And then I have other shameful thoughts “what will they think of me?” “I’m not good enough”
and finally when I eventually succeed in writing a few lines I think that what I wrote is not good enough to be sent.
And then I have to work again on it.
I’ve done my resume but I feel a bit ashamed of it when I should rather be proud of what I achieved. (I have a voice saying, “it’s not enough”)
I should also put my whole resume on LinkedIn explain for each position what I achieved but I don’t do it because I have this voice that everyone will see it and judge it.
It’s absurd and insane.
But I start to realize that all those thoughts and feelings don’t serve me but I’m not able to get rid of them.
Thank you in advance for reading my entry!