Prolly overheated the poor clutch. I had the same thing happen to me, intense stop and go, and steep hills.
My versa has 42,000 miles on it. It is a 2009. Yesterday I was driving in a city with some stop and go traffic and afew hills. Next thing I knew I heard my clutch slipping when I was trying to accelerate up a hill?? I backed off the throttle acouple minutes and it hasn't done it since?? What's up with this?