A lot of people have answered with suggestions to focus on one small thing at a time, and several have suggested version control. I'll go one step further: create repositories on your desktop machine, and work from those repositories. Update them regularly from whatever master repository the company uses. When (not if) there's a crisis because someone damaged the master, tell them that you can cut a new copy from your personal repository.
However, do not under any circumstances put company code on a machine that you personally own or take home. Because then you might find that, rather than being a hero, you're on the wrong side of the desk from a lawyer (at best) or law enforcement (at worst).