Very common. I was like this for years. All you worry about is what they think. It can be so consuming. It's more common than most people realize. Even people you'll be around and may look up to as 'cool & together' may also suffer from it (in silence).

Meditation helps - getting your breathing under control and preventing the overthinking is the aim - maybe try 10mins a few days a week. You'll find you become generally more relaxed and happy with yourself.

Getting to a point where you can be authentic is key (easier said than done for most of us). Takes time and practice. Try to work with yourself in a positive and loving way - try not to be too down on yourself.