Chances are, your toddler couldn't smash the toy into your head with enough force to cause a concussion.

Also, as it sounds like your head was resting against a pillow, there would be no whiplash effect, so your brain wouldn't have moved and smashed against your skull.

Penetrating injuries aside, so much TBI damage occurs from brain/skull contact, as opposed to purely skull/object impact.

Monitor yourself and try to take it easy.