It looks like you are depressed because you don't have close friends and somebody to spend time with. As everybody likes you and you are good at study and sports, you have great chance to make good friends. You should not be worry about that, its normal at this age.
Thank you I think that is definitely part of it
Wow I read this and I had to make sure that I wasn't the one who wrote this awhile ago. I am pretty much in the exact same position as you are. I am 15 years old (girl) and I'm a competitive dancer, so Im pretty much out for most of the night as well. I have a nice family and some friends but not a whole lot of close friends like you said. I get good grades and I couldn't understand why I was losing my energy (I was also very hyper usually). I was definitely stressed a lot about school and sports and I cried a lot. If you: find yourself sad for no particular reason, are more quiet than usual, not interested in your sports as much as you used to be, and just generally unhappy for more than 2 weeks it can be counted as depression. I didn't talk to anyone and eventually tried to take my own life. Don't get to that point. Talk to someone about how you are feeling now. No, this isn't just a "normal stage" that teenagers go through like James commented, but it is common. Just remember that this is one stage in your life and this isn't forever. You should be enjoying your teen years so don't let depression take that away from you by feeling "eh okay" most of the time. Talk to your doctor and who knows. A simple medication once a day or councling once a week might make you feel a lot better. But don't brush your feelings off as no big deal ok? You are important and if you aren't happy: change something.
ill help you asap contact me asap