Wear a padded hat like the Ribcap -
Soft Protective Special Needs Helmets for Adults & Children - Ribcap
It will give you a sense of security and reduce the impact from future head bumps. (I wear one everyday and then one day I forgot and felt vulnerable and exposed without it.)
While the impact force from those head bumps most likely isn't enough to cause a new injury, it is enough to trigger an inflammation response and the inflammation is what causes the symptoms. Plus anxiety can contribute to the inflammation.
So take a double dose of Curcumin and Fish Oil (both are anti-inflammatory and neuroprotective), rest a couple days to allow the inflammation to subside, then gradually resume your previous activity level.