Every person has a tough time at one point or another.
Having trouble with school does not make you a bad person, or a dumb person. Getting a bad grade, or not understanding a subject, means you need a little extra help to do your best. The most important thing about having trouble in school and is not to pretend it is not happening. At the first sign of problems, get help . Ask the teacher what you can do, ask the school what extra help is available, ask your parents what they can do to help, and talk to your friends, who may have had trouble, too.