I had severe mood swings over the course of a day for a few weeks. I ended up diagnosed bipolar 1 because they thought I was mixed, while like you, I thought I was an ultra ultra rapid/ultradian cycler.

Turned out it wasn't bipolar. I was reacting to stress, but more importantly, severe food allergies to gluten and casein, which took 20 years to learn that I had.

I'm most interested in exactly how you feel when you go hypo/manic then depressed, and your behaviors. Is the switch instant, or does it take a few hours to transition? How do your thought patterns compare between ups and downs? How do you sleep? What do you eat?