Sleeplessness, worrying about going to back to work the next day, thinking about work during your free time, wanting to leave but not having time to look for another job because you need to rest on your days off, feeling taken advantage of and overworked by your managers, knowing that you shouldn't be working so hard, your friends, family and your own life becoming less of a priority than your job. The list goes on.

And those are the early warning signs. When you actually have a burnout, you don't need to know the signs, because you just burn the hell out and there's no mistaking it. You're physically and emotionally screwed. Don't ever let it get to that point!