I'm wondering if it's possible to be bi polar all your life and not have it diagnosed until you are in your 40's. Back when I was a child, both before and well into my teens, I had manic and depressive swings. One minute I was up, the other I was down. Back in those days, there weren't the psychiatrists and all the knowledge we have now. I don't even think my mom realized that there some mental health issues with me.
The depression was really bad after I gave birth to my oldest child, flaired up as postpartum depression. That didn't happen with my youngest though. Now, I can tell when I'm manic much more so then when I'm depressed.