Dragonfly is right about DSM labeling, but feel free to call your disorder whatever you like. I can definitely relate to the moods you are describing. In fact, daily mood changes (short of true episodes) have been documented in people with bipolar. (see the thread "cycling within cycling")

If you are a true ultradian cycler, keep in mind that meds may not work as well for you as you'd like. I've heard that tegretol is the best for super-fast cycling?-but I could be wrong. Regardless, it would probably be a good idea to include therapy and lifestyle changes (consistent sleep schedule, good diet, other healthy habits that I've never managed to develop ) in your treatment regime.

I hope you feel more level soon!