Thank you all for taking the time to reply. You've given me things to think about. I've wondered if this is BPD too.

But yeah, these states or lifestyles or whatever do last a long time. They are also, as far as I remember, never changed because of any big blow-ups with people.

Maybe this is important: when I go into social mode, it's actually kind of hyper-social. I'm loving everybody, believing I'm an excellent person, joining many things, volunteering for many things--I get overcommitted. So maybe this is hypomania?

But then it also sounds a lot like hypomania when I quit it all and believe I can be really happy without people. I don't need them, or so the thoughts I remember go. And I feel ecstatic about that realization.

Then I get really unhappy about whichever choice I've made, until--Pop! Of course! I've been living the wrong way, for me! Changing to the right way will fix everything!

(sigh)