Yeah, it's like they've said. You only lose if you give up. As long as you keep at it, you'll find something you're good at. And if you want to speed up the process, visit a career counselor. I've done some assessments at my local community college that really gave me a lot of insight into my talents. Hell, I could start you off with a multiple intelligences assessment right now. It's a good way to figure out how you learn best and what your proficiencies are.
Birmingham Grid for Learning - Multiple Intelligences (Secondary)
I was given that assessment when I became a tutor at the public library over here. It's really useful and you'll definately discover something about yourself. Your school should be able to get you logged into wois.org to take their assessments. careercruising.com has a great career matchmaker assessment, too. Just ask someone at your school to let you do 'em and you might be surprised how it turns out.
There really are no losers. Everybody has talents, whether they know it or not.