Having one concussion
does not predispose you to having another concussion. This is especially the case because of the way you sustained the concussion - falling down the stairs - which is not likely to happen again! Multiple concussions occur most commonly in people who play contact sports like soccer and football. Even in this setting, having one concussion does not raise the risk of having another concussion, although the risk of concussion from contact sports is high enough that many athletes do sustain multiple concussions.
The worry about multiple concussions is that, since a concussion essentially represents a minor brain injury
, repeated brain injury can predispose to long term problems with memory and cognition and raise the risk of Parkinson's, dementia, and other degenerative brain conditions. These risks are not present with a single concussion.
You will want to follow up closely with your primary care doctor
to make sure that all of the symptoms of the concussion have resolved. Sometimes, certain concussion symptoms such as headache and trouble with memory can last for quite a while. Your doctor will help you monitor your recovery to make sure that you return all the way to your baseline level of functioning.