I love this thread because I can relate so well to it.
My gauge for whether it's "mania or me" is anger. If I'm in ecstasy about the magnificence of life I think that's wonderful. Whether it's mania or me, or both...doesn't really matter.
If, however, I find myself becoming edgy, irritable, anti-social, angry, enraged...that's a red flag for me. Being in that state is heading toward a mania that is dysphoric and out of my control.