I Dont Know Who I Am Anymore

I am a senior in high school and I constantly feel like I am missing out on all of these experiences that everyone else is having. I know I am young and still have a lot of time, but I see all these other people my age out living life and having fun and I just think high school is the time to have a lot of these experiences. I don't have very many friends and I never get invited to parties and stuff like that. Any help?