For me, I can feel the change quite fairly. It's almost exactly like those diagrams, Where theres just two arrows, one going up, one going down. Like, I am going up from depression to mania right now, I could feel myself just completely low just yesterday. (I may be a rapid cycler) like I just wanted to break down and cry my eyes out. Today, i could feel myself in a much better mood, what I would consider just an inch above normal level, not exactly mania though, towards the end of the day I stared to get irritated, so I hopefully will be entering mania soon
I love my mania...most of the time.