Two of my big fears:

1. Phone calls
2. Decisions/changes

From my own experience (so not necessarily fitted to you) if you sit thinking about it, the more you will worry and the more you will wonder about what will happen and possibly jump to conclusions.
It's your dream... chase it! Make those phone calls. What could happen... if you put it off, you will still be anxious. if you make those phone calls, your dream could start to become a reality.

I'll be keeping my fingers and toes crossed for you. I can understand how unnerving this may be, but think of what could come of it.
Good luck