Am I an idiot? please tell me?

My mom calls me that along with fat cow and so do many other people. My confidence is so low i cannot even concentrate on my school work,thus im struggling at school. My teacher said i was the most negative person shes ever met in her 14 years of teaching. Also i have no friends at school its my last year i just sit in the corridor . I don't know who to be live or what to think anymore ,should i just give up on life .