Wordpress CSS interface

I just lost 2 days of work because I thought it was a brilliant idea to just use the CSS interface on wordpress instead of updating my original .css file.  So when I updated my .css by accident it replaced the server based css with the original I had uploaded that didn't have any of my edits on it because I thought it would be faster to edit the CSS in the interface rather than edit the local version and repost it to the server.  NOOB! Lesson learned but Nothing feels worse than sitting on this couch for the past day and a half putting a site up to have it ripped down.  YAY! It was weird too because I was just working on the project hit reload and wordpress came up with 'oops there's no .css file on the server' I was like '?' and went to check it out...saw that it was on there I reloaded the page and it continued to say that.  ..wierd whatev'