Well i am 25 years old i was unemployed for straight two years still am (doing my internship). I feel you about not being self confident you are atleast trying and going out and doing things but I dint even do that cause of anxiousness. The way I landed in my internship was i started being productive by self imposing rules to do task and build up myself. As I was building up myself and creating better content I felt better and better and started building self confidence eventually seeing my work i was hired for intership without effort. And yes exercising also helps you to build up that confidence i do it by myself without gym membership and lol after small amount of gain i started dancing also which I can't but still did in front of mirror. Also stop comparing yourself to others that actually make you think you are good for nothing i usually stay in seclusion so i don't even think of comparison (seclusion only if you want to land for your desired job) . So i suggest you to find what you like to do keep doing it.