Your kinetic energy is low, but your energy remains mc2.
Technically, your mass is given by mo/sqrt(1-(v2/c2)) where v is your velocity and mo is your rest mass... though this is special relativity and doesn't account for accelerations...
therefore, if your mass is high and of course the conversion factor of c2 is pretty much enormous, then your relativistic energy is highly enormous...
EDIT: forgot sqrt