Orange Mexican Fire

Ok, i'm 13 im a guy and i lost 90 lbs and i feel good. I recently went on vacation with dad to see my grandparents. I ate a ton of food their. Fired ice-cream, mexican food, fried chicken, ice cream everyday, orange juice, cereal, english muffins, late snacks, granola bars, hamburgers, chips, salsa, nach surpreme at the mexican restaraunt, seafood, and I gain almost 10 lbs. But I don't look like I have. My dad says I probably gained 10 lbs of muscle because when I was their I was hitting the baseball around, throwing the baseball, shooting the basketball, I mowed the grass, I played pingpong, swam in the ocean, I did workouts on that thing called wii fit, I played bowling on it but I did mostly outdoor stuff with my arms and legs. So do you think I gained muscle not fat? I do workout and I don't look like i've gained weight but I don't look like muscle but I still gained?