When you want to change anything about your job, practice, career or life ... and fear or uncertainty stops you ...
Your are contemplating a step that is TOO BIG.
In psychology it is called "telescoping". Here is an example.
If you wanted to walk from one rim of the Grand Canyon to the opposite rim - on the trail that goes down and through and up the other side of the gorge (it's a thing...) - you would not try to do it in a single step. You would not attempt to leap from the south rim and expect make it all the way to the north rim. It would be scary (and most likely, fatal) to make that attempt.
This is telescoping. Looking from where you are to where you want to be (like you are peering through a telescope), noticing the huge distance and giving up before you start. It's such a long way. I will never make it.
NOTICE: If you don't try to leap the whole canyon in a single bound, there is a trail that takes you the whole way. You just have to take regular old steps, one at a time.
Telescoping is when you think about a big goal, notice the distance from where you are to where you want to be, and fear motivates you to give up.
This fear is also a clear sign to take a different approach