What is it about beginnings that scares us so?
They are similar to endings in this regard.
They share the same finality.
A beginning is an ending of one’s life, as it was before that beginning.
My strategy for making beginnings less stressful: acknowledge the life you’re losing. This change might be for the better (whether immediately or eventually), but you’ve had a good run without it; you’ve made it this far. This time, leading up to this change, has not been worth any less. It has had its own distinct use and worth, entirely unrelated to why you’re abandoning it now. It is worthy of respect and fond reminiscence.
Mourn it, and let it pass. Then move on, to your new beginning.