I am a lesbian and i've had my period of a non often on for two weeks and i am not pregnant?

Hormone: If not pregnant, irregular menses or missed menses are usually do to anvoulation or oligo-ovulation (not or only occasionally releasing an egg) there are a number of medical conditions that can cause irregular cycles or no cycles like pcos, thyroid dysfunction, hyperprolactinemia, menopause and others. It is important to see your physician.