Need Motivation!

First thing first. Don't call it a diet. They fail. Call it a lifestyle change becuase that is what you have to do. It is one of the hardest thing I have done to date. I too currently work full time as a teacher, part time a few nights a week, and I go to grad school. Oh did I mention that I too am a mommy. Take your kid out for a walk. You dont have to sweat bullets to call it a workout. Just get up and move. Stick with it.

I'm also a very busy mommy--I work full time (40+ hours) and go to school full time as well. I felt the same way you did..start a change, workout really well for a couple weeks and then like a balloon popping, BAM, motivation gone. I think what helped me is to think of this as a complete lifestyle makeover. I changed my attitude about food. It doesn't have to be super healthy, no mess-up days EVERYDAY. It's okay to indulge in things that you really enjoy now and then, just don't go overboard. Throw out all the crap in the house and replace it with healthy options for snacks. (I'm a big-time snacker so it was hard not to reach for the chips or cookies.) And when it comes to exercise, you don't have to go to the gym. Buy a couple different workout DVDs and switch them up a few times a week while your kid is taking a nap or entertaining themselves for 20 minutes. Go take a walk at the park with your kid in a stroller for a while. Have your kid exercise alongside you--make it a game. I've found that those little bursts of exercise is enough for me to get moving and feel good that I exercised, plus it doesn't take a long time to do so even if you're exhausted, it's only 20-30 minutes to get it over and done with. Just take baby steps and take it one day at a time. You'll find that it's easier to pick yourself up and keep going and it'll be harder to lose motivation.