How to determine you have bipolar disorder?

Eval: If you are concerned that you may have bipolar disorder recommend addressing this with your physician. He or she may recommend more comprehensive assessment by a clinical psychologist or a psychiatrist.

It's complicated: If by 'bipolar' you mean moody, I am sure your friends and family can tell you. If instead you mean having diagnosable mental illness called bipolar disorder, it is best to get a psychiatric evaluation as bipolar disorder is easy to both under- and over- diagnose, with potentially serious long-term consequences of either kind of misdiagnosis.