It can be difficult to tell exactly when you're overdoing it (in any situation in life).

But here we're going to talk about people who overwork :)

You take criticism very personally.

When work criticism causes an emotional outburst that ruins your entire day, it's a sign that your self-esteem has become entangled with your professional identity. 

Work follows you home too.

This goes beyond the occasional email after work hours. I'm talking about the constant noise of work in your mind during moments that should be yours. Whether you're checking email during family dinner or waking up at 3 a.m. thinking about meetings, you've lost the crucial line between work and life.

Your default goal is to please people.

When you find yourself compulsively playing the workplace hero – never saying no, always being available, constantly putting the needs of others before your own – you are likely very emotionally invested. 

Your work is becoming your identity.

If you have no self-concept beyond what you do for a living, you are in dangerous territory.