Thanks for choosing health care magic for posting your query.
I have gone through your question in detail and I can understand what you are going through.
If you have fallen backwards and then you have had a nasal bleed then it is always possible you might have had a head injury
especially when you are having a sever headache.
You should undergo a CT scan
Hope I am able to answer your concerns.
If you have any further query, I would be glad to help you.
In future if you wish to contact me directly, you can use the below mentioned link:
Wish you good health,
Dr. Srikanth Reddy M.D.