Why have i lost so much confidence unexpectedly?

maybe the more you started to think when you were around people the more you grew paranoid about them not liking you. i think this problem is all in your head some people mistake confidence with being well sociable in a group but confidence is being able to stand alone and not fall. what you need is a big inhale and exhale and think of something that relaxes you like a good joke to keep your mind off of wondering what people think of you. and just walk in the room without a second thought.

It can be part of growing up. Your brain and hormones are changing. So you notice more now or react differently now than before. Whenever you feel self conscious take a deep breath and relax. Think to yourself "is this really a big deal? Or am I overthinking this?" Chill out and have fun! Easier said than done I know. But just try and enjoy yourself :)