When we’re attempting something big, greater than ourselves, and it’s scary. The story or stories in our head can be overwhelming and not in a good way.
The best way to get out of your head is to take (the appropriate) action and press forward. Identify the block, why it’s a block, and the best plan to move through it. Not around it, but through it.
For some extra help, take a listen to this reading of “Mike and the Dragons”, by Jocko Willink.