confidence

whenever im in my room alone on the weekend I think to myself, yeah why am I so shy when I can literally be confident? be who I want to be, show my true self to people at school but then when I get to school, I'm completely SILENT. I don't know how to communicate/start conversations, I get so awkward I HATEEE IT, why do I have the confidence/no fear of anything mentality before school but then when school starts Im back to what I was originally, awkward/quiet/shy/no social skills UGH SO ANNOYING.