Re-inventing my diet regimen

I ate a rather poor diet today.  I usually tend to consume poor diets whenever I decide to go to a convenient store for brownies and candies.  I did in fact go to a convenient store and purchased those items.  The problem is that not only did I feel no guilt from eating those items, but I ate unhealthy when I don't mean to.  This was a case of low self-esteem and just giving up on myself.  I lost weight, but I am losing it the wrong way.  Now it is time to lose it the right way.  Consuming sweet potato pudding and bowls of macaroni and cheese are not going to help.  So, where should I begin?  At breakfast time and snack time, I tend to consume fruits and vegetables and dairy foods, which I did.  I start off well during the day, when I actually eat breakfast.  I am not usually hungry during those times, but eating breakfast, even an apple, jump starts the day.  That is the usual advice for breakfast. Should I eat larger breakfasts, lighter lunches, and even lighter dinners with three snacks?  How should I eat during the course of a day?  Where should I begin?