I too have trouble figuring out when I'm mixed, but one episode stands out in my mind, I mentally was depressed (suicidal, had no joy or anything) yet I had tons of energy. I remember getting in my car, purposely not putting on my seatbelt, and driving as fast as I could because I had so much energy, yet I didn't care if I died.
I heard mixed states are actually most dangerous for those with BP because of suicidal ideation with the energy to actually act on it.