Hugs, Hun,
Any major life change results in a little depression, and you are going through two of them - quiting smoking and lapband surgery. I think you are handling things GREAT!
One thing my therapist has told me repeatedly is that if I am feeling depressed, to leave the house and do something that I have never done before or haven't done in a long time. I have gone to the library that just opened, gone shopping at stores I never have been to, gone to the park and fed the ducks, found a garden at the museum and wandered through it.... you get the idea.
Hang in there!