'Nerd' and 'loser' are put-downs. They are labels or over-generalizations. So, for instance, I have nerdy traits (I'm studious and not very athletic), and there are lots of things at which I have failed (being popular at school, etc). But, that is not all I am. the Truth is much more complicated! I am also funny (I have a good sense of humour) and I have my successes (I got through school, somehow). It is important NOT to give oneself demeaning labels because through them you will have a distorted idea of yourself. Others may try force these labels on you if by doing so they get to feel superior. Or if, by doing so, other people see them as powerful for putting others down (they may get social cred out of it). THESE ARE NOT GOOD REASONS TO USE SUCH LABELS ON YOURSELF. Don't learn to abuse yourself, even if others are abusing/bullying you.