Unexplained weight loss??maybe?

well, i was 151, and now im 142. I HAVE BEEN TRYING TO LOSE WEIGHT. but i didnt think i was actually succeeding with it. I dont know though..maybe i was. I used to drink 3 cokes a day. about 3 months ago, i completely gave up cokes and now i just drink water. i used to eat poptarts and waffles , now i just eat cereal in the mornings. i have been trying, but its just been minor changes. i go out and dribble the basketball for like 2 hours a day. we dont have a bball goal right now, so thats all i can do. i am a 13 yr old girl. could i be getting taller? could i actually have been succeeding with the weight loss? could i have an infection? it has been itching a lot "down there" lately.