Absolutely agree with lunaaabelle, you need to have your head skrew'd on straight! One of the best tips I can add is to build a good pile of healthy tasty recipes(and snack options!), recipes that you are going to be excited to try but are 'on plan' and make sure you have enough to give yourself as much variety as possible and try as many new things that you can. Prep is everything!
Starting is the hardest bit. You've done this before, you can definitely do this again! All the best!