When I walk up stairs I trip, not even thinking about it. Is there a term for this or anything?

Clumsiness! Sorry, that was a bad joke. You should see your doctor and be evaluated, especially a neurologist. As you did not say how you walk, you could have a foot drop without realizing it and it could be from your spine. Treatment would be directed on the cause and a simple physical therapy may help. It is a risk for falling so be careful. Good luck.