This is the time for you. Of course even though you are busy you want to enjoy it as much as possible too. Try not worry so much of what others think of you or what others are doing. Everyone has their own life and interests. This will become more evident as time goes on. Everyone will go different ways especially in the next few years. But this is a positive thing because everyone grows. It is sad because as you all graduate and move onward with your lives you will miss this time. But again this gives you the next step in your life and something to look forward too. You always have social media and can keep in touch with high school friends but eventually you will meet more best friends along the way to the things you want in life. What is important is you doing the things that help you get to where you want to go.
Social skills are another area that you learn during school years, from building and learning about friendships, who you can trust, how people might change as they go from one grade to another. Some friends move on with other interests, while you remain friends, but some just move onward. Its about life and this continues throughout your life. Its interesting and what is most important is being true to your, respecting you and treating others like you like to be treated and for those who do not treat you this way, you learn to stay away from so you can grow and be happy. Remember a true friend who cares about you will always support your dreams.