I'm trouble concentrating in class; what can be done for this?

Evaluation: Difficulty concentrating in class could be due to many factors. Assuming it is not the environment possibilities include anxiety, depression, boredom, sleepiness, attention deficit, etc. Talking with your primary care physician would be a great place to start.

Do you have a: history of ADHD, depression, or anxiety? Are you stressed about work, relationships? How's your diet, exercise and sleep? Basic questions, but all influence mental function. A psychologist can help zero in on the difficulty in short order. (Maybe you just don't like the subject being taught or the teacher...?)

Eval: I would suggest a neuropsychological evaluation to assess the possibility of a learning disability. Neuropsychology is all about testing, and not about therapy. A battery of tests are administered, a report is generated, recommendations are made, and the results of the report are explained to you. Good luck.