Re: Unnecessary worry
Let me give you somethng to worry about then…
You are going crazy! 
Joke aside, The problem there is not that you have nothing to worry about, it is the state of oblivion you have for a short period of time which makes you less worried about somethng worrisome, and your subconcious tries to wake you up to reality and you become worried of not being worried.
Makes sense?
P.S. It is somewhat like someone takes inoxicant and stops worrying (for time being) but as soon as the effect wears off, person gets overwhelmed with anxiety.