Thanks for posting on HCM,
and worrying can amplify the already existing problem that you have. Yes it is true that after hitting your head hard on something anything could happen within and/or without your skull and you presenting with those symptoms indicates that you need medical attention with imagery scans to determine if anything is actually going on within your head.
You might just be experience post traumatic migraine
which require just antimigraine medications.
You may consult an orthopedic surgeon as soon as possible so you can properly be examined and appropriate treatment provided.
Hope this helps