I think I'm a loser.
That's not good. Why do you think that about yourself?
I'm not good at anything.
I see you're feeling bad about yourself but don't call yourself a loser. Think about the positive aspects of your character.
I can't of anything.
You should not call yourself a loser, it will make you feel more like a loser and it won't help you think of anything that doesn't make you feel like a loser. Maybe you should ask the opinion of others, they might be able to think of something.