I have to agree with others. Cardio is the least important factor if you want to lose weight. Diet is by far the most important, followed by strength training.
5 lbs weights with tons of reps does not sound like strength training to me. Personally, I would just ditch cardio all together because its sucking up a lot of your energy and willpower. Well, just do some daily walks. THat should be good enough.
I think you are eating far too little. That sounds like a crash diet to me and those never work. A proper diet is all about developing sustainable habits. Cut sugar, cut processed foods (this includes processed grains) and eat high fat, high protein food along with heeps of veggies. I wouldn't bother counting calories, just control your portion size. That will be a very satiating diet.
I recommended this book in this thread already, but I think it is fantastic.
The Power of Habit. My problem has always been overeating due to boredeom. I eat very good foods, but, well, a whole crap ton of fruit and dairy is going to put on weight no matter what. This gave me an understanding that you simply can't tell yourself you will use your willpower not to eat. That will not work. You will lose in the long run. You have to identify how your habit works and then change that habit into a better one. So boredom -> eating went to boredom -> consciously do something interesting/engaging.
Also, do something about your stress
http://en.wikipedia.org/wiki/Allostatic_load
Stress is no joke.
