Other: Gamma Ray Burst.
So I survived (how?), and now. . . well, the atmosphere is kind of toxic, everything living has been fried and everything running of electricity has been fried. The ozone layer is kind of missing so going out during the day would fry me. Also, the toxins in the atmosphere would likely cause global cooling, which would make it cold, so going out during the nights could be bad as well.
On the bright side, I don't think a weapon of self-defence would be needed. Then again there's no way I'd survive past the initial surviving of the actual GRB anyway. At the most I'd survive a few days before I'd die from exposure to toxins/radiation/whatnot.