Fingers crossed for your Seroquel working. I don't know if this would be of any help, but... You've pretty much described a very typical energy pattern for me. I don't even tend to think of it as cycling, but more... oh what did they used to call it? Biorhythms? The way some people just tend to be "morning people" or "night owls" or tend to have a low spot of energy near the same time everyday?
I've got what I think of as my "real" cycling, where there is a pretty relentless tilt in one direction or the other. Then something I think of as "cycles within cycles", where things get bouncy in the midst of the larger picture. Then just plain old biorhythms. I don't know how scientific this is, but it's just the way I think of it. It helps me worry less, like short term things might just be short term things and not necessarily heading somewhere big. That said, there are times... just a certain feeling I get that has proven to be a pretty good indicator of something bigger on the horizon. But that doesn't happen as often as the wobbles, and helps me worry less. Does this make any sense? (It might not! )
That said, everyone knows their own indicators and typical daily energy fluctuations best. Just a way to look at it if it sounds familiar.

Sweet to you, BNLsMOM!