Yael, you poor thing, it must be so worrying for you, I hope all is well very soon. I would think concussion can easily cause a change in behaviour. I also know whenever my DD's are sick in anyway (even runny nose) they're not themselves. So it may just be still getting over concussion or nightmares causing him not to be himself. I hope the xray comes back all clear and DA returns to his old self asap. Thinking of you and never blame yourself, although that's what mums do! xoxoxoxox