1) EAT MORE
Hun, if you are training 6 hours a week and you do not want to lose weight, you must start eating MORE. If you're training, you're burning calories even when you're not doing anything, so EAT. Please eat! And I hope you're stacking in the carbs, because a body without carbs won't function well. When you workout your body needs sugars, fats, carbs, and protein. You need to start treating your body differently. Immediately after a strength training workout, consume a milky protein shake or a chocolate milk shake. The choccie milk shake has loads of calories and good fats and your body NEEDS it. After a cardio workout, drink an electrolytes water (or celery is good because it's packed with water and sodium). When you sweat, you lose salts/ sodium from your body and you must replenish the stores. Also increase your portion sizes, and make sure you've got a nice balance of colour to your food (this will ensure you are eating the correct vitamins and minerals).
2) EAT CARBS AND FATS
Make sure you're eating lots of complex carbs MIXED with simple carbs (such a quinoa and potatoes) and healthy fats (almonds, olive oil, avocado, custard apples, milk, yoghurt)... When you mix complex and simple carbs, your body metabolizes the fuel better. Fats are also necessary for a woman's body to stay healthy. Plus, I know what you mean re: the boobs- I feel effeminate when I'm a surf board too
3) DRINK WATER AS WELL AS EATING WELL
When you drink water, it fills you up - you'll *feel* full. But you're not full. Don't let water fool you into thinking you're not hungry. Eat your meals, but drink water as well. Continue your water intake. Also be aware that plain ol' water may not be the solution. You may be losing sweat-weight (as mentioned above). You *NEEEEEED* to replenish salts lost during workouts.
[Advice from own experience, also train with a coach for long distance running]