Bipolar Disorder?

Around July until November last year, I would always get moody around my period. Which is abnormal for me. But since December, it is almost every day. Even when my period isn't close. I'll be happy. And then I'll change, and be extremely mad, and hate everything. And then I'll get happy again. And then I'll get sad. And cry for a long time. And the same thing keeps happening. It's like a the same cycle about every day. And I hate it. I know how I want to be. I know how I should be. I have a great life. I am in a long term relationship filled with love. And how I am is starting to negatively affect it. I am not diagnosing myself with bipolar disorder or anything. I just don't know what is wrong with me. I don't like it. I want to be myself again. Does this is sound like bipolar disorder? If not, or if so, should I see a doctor or a therapist?