I agree with grammercie. You may still ultimately decide this isn't for you, but take your time and think about it. I applied two years ago, was accepted with funding, then deferred my acceptance to take a very exciting job. I then deferred another year to think it over and ended up reapplying to the same programs that accepted me before, although I am now in a much weaker position than I was after my initial acceptance. (Funny how they don't trust you after you keep them hanging. )
I've also found that a second visit to the campus can sometimes really change my perspective.
Think it over, then do what it right for you in a week or two.