I can also relate. Rapid cycling and mixed seems to be mostly my experience of bipolar in the past year. Physically I will feel exhausted, even be in pain as if I'm running a fever and have no energy, but at the same time I feel restless (even if I can't even walk around aimlessly) and my head is overworking and of course it resists sleep as if it was poison. I can't understand this mixed depression(?) either; the only way I can explain it, is that your head reacts to the depression by trying to rush into hypomania but because your body can't follow you become agitated and wired (and possibly quite irritable at times?) But what to do about it....I don't have any suggestions apart from trying to get your body moving at least to a minimum and have a sort of schedule with set activities during the day and a wind down ritual before bed. Even if it doesn't make a difference to how you sleep (or don't sleep) at first, I think it is a step to trying to harmonise what your body and your head are doing... (And of course see the doctor if it carries on - especially if you don't sleep..)

I hope this helps a bit, I'm sort of new to this too!