Concerned over the amount of calories...

I am basically new to counting calories, basically I am a Weight Watchers girl but I wanted to track my calories to see where I am at... After entering in my info, weight, goals, etc., I see I am only at 1200 calories. This concerns me as I am a distance runner - currently training for 2nd half marathon, and also crosstraining. It does not seem like enough calories to give me the energy I need. I guess all I can do is try it out. I really only need to lose about 6 or so pounds.