Write down all the things that go through your head. You will see they are not that many.
When you think of the same things over and over, you feel overwhelmed. But when you write them down on a piece of pape you realize the volume of your to-dos is much more manageable.
Scheduling your day won't take you long and will be a substantial anxiety reliever.
The day ahead won't overwhelm you and you will be able to focus and enjoy it.