A new leaf . . . ?

Every time I begin to feel a little bit better, get a little more energy, start to feel an inkling of motivation, I decide to turn over a new leaf. The problem is that the new leaf quickly turns into a forest. Here's my most recent forest I decided to turn over last night:

• daily exercise w/the dogs
• work 5 hours a day on my dissertation
• organize my office
• organize my children to daily and weekly chores
• start eating better
• read from scientific journal every day
• keep house cleaner
• have meals planned out for the entire week
  

and the list goes on. Once this happens, the depression starts creeping back in. It is a conundrum. I know I should just start little; the problem is that after lacking energy and enthusiasm for so long, a little bit makes me giddy and it's like I get drunk on just a little happiness. But then I end up with an emotional hangover. So what's a gal to do?