its hard to reconcile the focussed intensity of creativity with the next part, which is way more ominous,abstract and full of possibilities.. releasing something into the world.
You probably feel the way you do just because you care about what you do. its a good thing to feel.
Dont forget, a great part of software is that you can kinda keep something AND give it away.
as opposed to, for example painting art, where if you have to sell it in an unadulterated form, it cant be fully duplicated and you literally have to part with it forever.
I used to make some one off electronic devices and sell them. killed me every time i had to say goodbye to one :(
game devs have it easy in comparision IMO. its great to being able to share something and keep it, to work on some more, at the same time.
bit of a rant there hope it makes sense :p i dunno its late.
hope everything goes well for you.