Why am i gaining weight?

Hello,

You mentioned what you drink (48 ounces of water per day...which is excellent), but not what you eat or when you eat. You also did not mention what type of excersise that you do.  With that much water per day, you should be eliminating two or three times per day (bowel movements). Are you? At your age, it could be a simple issue of beginning mensrtuation or muscle building. Your body is changing. Don't add stress to your system at this point. Walking is a great excersise....If your school has a track and field area, try walking around the track once a day. Put on your headphones and go for it!!!