Why won't my dslr record video for more than few seconds?

I have a canon eos rebel t2i. I have a class 10 16GB memory card. When I try to record video my camera will only record for a few seconds and then these little bar things on the side fill up and it stops recording. The screen will say "movie recording has been stopped automatically". I got a class 10 to avoid this and yet my camera still does it. How do I fix this?