I think that 2-3 hours of work a day is more the norm than the exception with programmers. Basically it is hard to keep your concentration for 8 hours straight without some kind of break.

How many comments on /. Reddit and YC news do you think are written during work hours.

So basically I think that you shouldn't feel bad about it if you get stuff done. Better 3 hours of pure productivity than 8 hours of mediocre bugridden sloshing around..