My therapist tells me the same thing. She says I don't know how to be happy or "just be." When I'm happy I almost feel scared, like I'm challenging something. I also feel like I know what you're talking about with the "Tasmanian devil" state. I've experienced those feelings as well, feeling bursting with energy, needing to destroy things or otherwise just release the energy somehow, even if it's just creatively....
My therapist says I'll have an easier time feeling happy when I finally feel safe. The only thing is I don't know how one goes about feeling safe and she's not giving me tips. -.- I'm almost always in alert mode, I guess.
Anyways I'm glad you feel you're improving and getting better, no matter how small those improvements may seem at the time. Keep it up!!