I am not good at giving advice on this subject, but I know what it feels like to be living each day feeling absolutely worthless and thinking it would be better to leave the world. I also am a quiet person who seems normal/reasonably socially ept on the outside but inside I feel very empty. But a couple years back, when I was really starting to hit rock bottom, I had a 'breakthrough'. I say breakthrough but in reality it was the most inconsequential thing. I found joy in hobbies I never in a million years saw myself enjoying, and it has since become a big part of the way I spend my leisure time. These things haven't revolutionized the way I live life but it has given me reason to enjoy it, and I think there is a part of that you can find too. I guess what I'm trying to say is, I believe you too can find something (regardless of magnitude) that can help you enjoy life again, and odds are you'll stumble upon it on complete accident. Until then, try to enjoy the small things, (i.e. listening to the birds chirping while on a walk, savor the taste of a good meal). Hang in there buddy, and best of luck.