Why should I live? I am only damaging the world with my existence.?

Because you're beautiful, and someone out there loves you. You mentioned if you have any children, they'll love you!! You're only 19, you have years to figure out what you can do, and maybe it's good. Not everything requires an education, you can find something. Even if you believe nobody loves you, somebody does. Maybe you haven't met them yet, maybe you have, but neither of you have realized it yet. As for the stress and anxiety, start with something you may love, take it slowly. For example, nothing real physical is ART. one that anyone can learn, without any physical labor is Art via the computer, such as photoshop, illustrator, or flash. Just go to Google, type in "(which ever of those programs you want) tutorials" and slowly begin with the basic tutorials to get a feel for it, and begin the non physical learning!!! and if you know anything about it, it's about expressing yourself!!! So express yourself!!! plus, art requires NO school education. Make art, or something that you can do and enjoy, your anti-depressant!!! Just remember, someone out in the world loves you.