I can think of a couple of things that might be causing this. How many carbs are you eating a day? I know on the days I have higher carb days, I get hungry more often.

The increased excersize might also be a factor. You are increasing your metabolism all the way around. Your body will continue to burn fat hours after a good workout. I would think that considering this, you could probably up your calories a bit as long as you kept your carbs at the current level without it hurting your weight loss.