If oversleeping ends your career, its not your career, it's wage slavery.
If you oversleep by hours or days and your boss says, I was worried. Are you all right?
And you reply, yeah, I overdid it last night. I'm just exhausted.
And he says, that's a relief. Can we still make the deadline?
And you say Barring further unforseen problems. Yeah. I have the prelims already.
And he says, You're the heart of the team, Larry. Email me the current version after you've had some coffee.
That is your career.