Over eatting
The recommended calories are based off of weight and height and where you are currently at and your activity level. If you want to maintain your weight, loose weight, or gain. Obesity Help has a calculator where you put your numbers in and it suggests how many calories you should intake daily. Here is another one to check out
http://nutrition.about.com/od/changeyourdiet/a/calguide.htm
One of the wonderful things about the DS during the first few years is you really do not have to be too mindful. But when you are years out this will be the way you can maintain or continue to loose.
These are some awesome 100 calorie snacks
http://www.obesityhelp.com/articles/20-snacks-that-have-100-calories-or-less/
While fruit is good for you most are high in calories and natural sugars. Veggies are pretty much "free" if you eat them raw (or cooked if nothing is added to them).
You are doing fantastic! Try to get your brain to remember that you are eating to live not living to eat! As soon as you are satisfied during a meal stop eating. Do not push yourself to clean your plate.