Pression about a commission

I’m a freelancer. I’ve accepted a new commission for new clients. I had asked for a much higher price than usual. They said it was too expensive, so we agreed on a price they could afford. It’s still very well paid to my standards.

I feel a kind of nausea when I think of this work I have to do. I guess I put pressure on me because I think: this is well paid, I’ve got to do something good, I don’t want to disappoint them, I’m afraid they are expecting a very good work because I’ve asked for a lot of money.

The worst that could happen would be that they don’t like my work, they would say: “we are very disappointed” and I would feel shame. It’s like I’m already experiencing this shame.

Would you have any advice? Thanks a lot.