hey, I'm 23 and I know how you feel. I know how hard it is. Your feelings are valid just like mine and many people who stutter. You don't deserve to suffer like that. If you can, get psychological help for the negative beliefs you have about yourself. You deserve to have coffee in the morning, have a little walk while listening to your favorite podcast, feel the sun, enjoy your favorite food... while you can do all these amazing things in life, do it. Being able to experiencing these alone mean life is worth living. I'm sending you lots of hugs. Just know that you're not alone in feeling like this. There is nothing wrong with you. You don't have to contribute to anything to enjoy life.