If I were the last human on earth I would definitely just fulfill my gamer needs. As most foods nowadays can be saved up for a long time, I would not worry about that at first.
I would think a lot about how it would be to do all the stuff I'll be doing if there were other people around (like finding a way to travel to various places, or coming up with a new idea of how to smash something that now exists in a massive scale. I would miss some stuff, be grateful that some other stuff is gone, and pretty much do as I please for at least half a month. Then I'll notice how pointless doing a lot of stuff is, since there is no-one to share you accomplishments with.
After that I would just try to achieve impossible things on my own, like playing football, or beating a wall in a tennis match.
This is all of course fictional thinking, because I believe in reality what would happen is this:
You would realize how much our society depends on other people doing their thing, so if it's only you: who's gonna keep things like electricity and internet properly functional? who is going to treat you if you get sick? Let's say that you find out a way to handle this on your own, and it is not a big deal; in that case, you will succumb to schitzofrenia after copiously masturbating to internet porn, missing the members of the opposite sex, and would be found dead by the lifeforms from another planet coming to occupy this one, with a strange look on your face, as if you were amazed by something in the sky.
This will surprise them at first, but then they'll realize you died of a heart attack caused by the high level of insanity you achieved by playing multiplayer with yourself and your imaginary friends, and having already lost two matches.
All the best.