You run 6 miles a day, 6 days a week plus extra cardio, and you are only eating 1300? Is that right? Are you weighing everything and absolutely certain on intake? If so, I would think you have or will have energy issues at some point (unless you are not logging accurately). That really is no where near enough to sustain that kind of activity.

http://www.myfitnesspal.com/topics/show/1080242-a-guide-to-get-you-started-on-your-path-to-sexypants

Read that link from top to bottom, and then reevaluate your intake/output/goals to make sure they are reasonable before you get too frustrated. And yeah, 30 days is not long enough to judge if it is "working", but really, make sure you have all your numbers correct before "wasting" that 30 days on something that is "off" already.

For comparison - I am 5'5", 132 pounds today, do little cardio (maybe 20-30 min 2-3 times a week) but do lift weights regularly and I *maintain* on about 2000-2200 calories a day. If I drop to 1700, I lose weight slowly (I dont want to lose anymore at this point). Everyone is different, but you can definitely lose weight eating more than you think, and by eating enough to sustain your energy output, you are more likely to be happier in general (not hungry and cranky) and you can sustain this lifestyle for much longer than you could a very low calorie one (meaning you will keep the weight off longer/perm!)