Why am I gaining weight instead of losing weight?

I've been exercising steadily for 2 weeks now. I burn about 400 calories every day. I eat about 1600 calories per day. I only lift twice per week, but do intense conditioning cardio for an hour every other day. I'm a 16 year old male, weighing 145 pounds. I gained 2 pounds so far. I drink a sufficient amount of water every day. This probably isn't muscle. I don't see a difference in the mirror.