Starting Over--Again

It never fails, I start a new diet and exercise routine and by day three, it's blown in some way or another. The kids get sick, too many errands to run, someone has to finish off the last three pieces of cake---whatever the reason, I'd always feel frustrated and annoyed at myself for giving up so quickly.
Now, with my book Worth the Weight about to be completed, I started to really read my character, Megan, and realized that she didn't start with everything at once.
One week she changed her food choices, the next she started working out.
I'm on week one and so far, I've done well. I've not cheated, I've stayed with my goals, I'm not starving myself nor am I eating nothing, but bacon. I've found a good routine that I can stick with even after I get to my goal weight/BMI.
Then next week comes the exercise--hopefully, I don't jump into the deep end and beat myself in the process.