How could I have not lost weight??? Yesterday I had a bowl of fruit and bran flakes cereal with skim milk.?

Then I had some coffee with sweet n low. For lunch, it was two chicken tacos, which were small, not restaurant tacos. They only had chicken pieces and hot sauce in a maiz tortilla. I also had vegetable soup. Then for dinner, all I had was a really big bowl of cherries, since i was in a rush. I've been going to the gym everday for two months. I do one hour of cardio everday and 15-20 minutes of strength training after. Could I have gained 0.4 lbs. of water weight, or muscle? What's another way to tell if I'm losing weight or fat?