Is it mania? I don't know, ever get mixed mania James? Manic energy, head so fast thoughts just become fragments, physical and mental agitation so bad your not sure which way to move, but you have to or you feel like you will explode, but you feel depressed and not euphoric. That's what I feel when I am mixed.. kinda like what you are describing, feel pretty done, but nothing will let me finish.... frantic chaotic energy and thoughts, well maybe pieces of words.