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From a "signs and symptoms of bleed in the head" standpoint, unusual sleepiness, nausea/vomiting, worsening headache, or focal neurological deficits (such as numbness or weakness, vision loss, speech changes, balance problems, etc.) should cause you to immediately go to the emergency department or call 911.
I always tell my patients--especially those taking blood thinning medications (aspirin, Aggrenox, Plavix, Pletal, Coumadin, etc.)--that if you fall and hit your head, it's never a bad idea to go to the emergency department and get checked out. There are a lot of people walking around in the world with bleeds inside their skull (such as "subdural hematoma"--where blood lies between the brain and the fibrous covering around the brain) that don't even know they have them. Most will never have significant symptoms, but some may get weak or have seizures. If you choose not to go to the emergency department, at least have someone stay with you, and both of you watch for symptoms I listed above.