What do I have to do?

What do I have to do?
When?
Today.
God's will!
What's that?
Look after yourself, be useful, have some fun.
What if I don't achieve what I think God's will is?
Either it wasn't God's will, or you didn't have the power to do it.
What do I do then?
If you definitely didn't manage to do God's will, ask God for the power to do it at the next available opportunity, since the power has to come from Him.
Is that it?
Yes.
No fretting?
None at all.