Remember that muscle weighs more than fat.  An increase in muscle will also require more energy for your daily non-workout tasks.  If you are increasing your exertion in your workouts and increasing your muscle tissue, you will need to also increase your intake.  One suggestion is to try eating high protein and veg. and lower carbs "snacks" every two hours.  Don't skip eating either....if your body "realizes" that it is not getting in calories on a regular basis to sustain your workouts, your metabolism may kick into a "reserve" mode and it will essentially store away the food that you eat instead of burn it.   To help keep it in perspective, pay more attention to the physical visable results and not the number on the scale so much.  That's hard to do because we like to look at the numbers to see progress, but two people weighing the same may be very different in health and their appearance because of the ratio of lean muscle and fat that they both have.

Best of luck!  Losing weight is really hard.....keep at it, though!

....."but I have promises to keep and miles to go before I sleep.  Miles to go before I sleep."  - Robert Frost

I agree with everything others are saying in regards to weight.  I had never really weighed myself until I started to become a "runner" and it was only because I was looking to lose weight.  However, this sort of turned into an obsession and at the same time I was not eating nearly enough considering the amount of mileage I was doing.  Since then, I have learned that you need many more calories to be able to keep up your endurance and fitness; this was tested for me last year in my first triathlon.  I have not stepped on a scale since then, and again don't really find it necessary, as it does not accurately reflect how my body feels in any way.  I say throw it out!

I would encourage you to consume the majority of your calories before 1 p.m. if you are still really looking to lose weight.  This has really helped me maintain my physique and stay toned.  Yes, everyone will have their slip-ups, but generally, I try to live by this.  A big breakfast always gets me started, and snacks every hours or so keep me going.  Eggs, fruits, yogurt, fiber bars; these are things that I consume on a regular basis.  Dinner I try to stick to lean protein and vegetables. 

CUT OUT SODA completely if you have not already done that!  Stick to water!

I am sure you are doing great!