First of all, like the others said increase your calories. Your metabolism is probably super slow. You can add additional fruits, veggies, nuts, whole grains and/or lean meat to your diet. You need to add another snack and probably have something like cheese/yogurt and/or something whole grain along with fruit. You could also start drinking green tea to help boost your metabolism.
Instead of running 7 days a week, add at least two days of strength training instead of running. My gym offers a weight lifting class (Body Pump) that I take because I hate lifting free weights though you might like it if you like running on a treadmill. Lifting weights helps you lose weight because your body will burn more calories when resting.
At 5'2" 118 pounds is probably pretty good if you have a lot of muscle. Just because a chart or someone else says you should weigh less that doesn't necessarily mean it's so. If your gym offers it, get your body fat composition tested. That is more meaningful. If you want to lose weight in your stomach, do ab work. The weight lifting will help and some gyms offer short 20-30 minutes ab training classes. There are also videos that concentrate on this area. If you eat lots of sugar and white flour products, some people carry more weight in their midsection. If the spot training doesn't work, try that.
