This is an expression you might say to someone in the morning if that person is grumpy or in a bad mood. However, they might not appreciate your comment if they are in an exceptionally bad mood, so beware!
Here’s a sample short dialog:
Cathy – I hate today. I spilled coffee all over my shoes and I just want to go home.
Penny – Did you get up on the wrong side of the bed?
Cathy – Yeah, that about sums it up.