I've started ultrarapid cycling with highly unstable mood and definite ultradian cycling now and then. It's related to medication experiments I am doing with my pdoc. And most observers would not notice anything, no, because I am so effective at hiding it.

I track my mood pretty religiously and would call what I am experiencing, which is similar to what you've described, ultradian cycling rather than a mixed state, at least for me personally. I can crash in well under an hour, sometimes recover, crash again, etc. It does not feel the same as a mixed state and I've been in a few of those in the last year. For me a mixed state is pretty sustained symptoms of hypomania combined with intense rumination, anger, etc. Can very rapidly turn to euphoric hypomania which will fade over hours to maybe a day or two. What I am going through now does have a lot of similarities to that but it feels quite a bit different. I am far more withdrawn and the euphoric/enraged moods tend to fade a lot quicker than in a mixed state.

One thing that is DEFINITELY true is that my behavior can drastically improve my mood even if I crash right after. So, going out for a walk. Or to do something that distracts me. I even had to babysit the kids here and although they are typically a huge factor keeping me hiding in my room, they were being pretty good, I was badly depressed before, mood recovered quite a bit during, and then I crashed right back. Made for quite the spike in my mood graph. But the point is, while I was doing something other than hiding, it helped.

For me it is so hard to stop hiding though. It's gotten really bad over the past few months and it wasn't great before. So it's hard to do the behavioral activation and make myself feel better.

I also know that zyprexa would likely vastly reduce this. There may be an antipsychotic that will work for you. This ultrarapid/ultradian cycling I'm having right now is because I switched antipsychotics and the new one works differently, but I have to go through it long enough to find out whether the new one helps the depressive phase (it does, a lot, when I crash I recover SO much faster) before we decide how to control the cycling.