By definition, if you have ever met the criteria for a manic or hypomanic episode that was not caused by drugs or medication, your diagnosis would be bipolar even if you are predominantly depressed. There is no maximum length of time for bipolar or depressive episodes, although a long period of having some of those symptoms might suggest dysthymic or cyclothymic disorder, which are more ongoing and less episodic. If you have questions, your pdoc should be willing to discuss your diagnosis with you.