You've really made an effort to understand yourself and monitor your emotions. I think you are just going to have to wait it out til Friday. And you definitely seem to come armed with some ammo for your appointment.
I'm sure that your doctor will be able to start a diagnosis of something, or least of all give you some anti-depressants to help you through this. It's not your fault, so don't feel guilty.
You have really considered your responsibilities which could not have been easy. Try keep yourself occupied and work, and for the time being wear that mask - you don't want to be hauled in by a manager and at this moment in time don't have an explanation for your emotions.
Surround yourself with positive people, when you have any free time, use it to relax and pamper yourself - you are number one in your life; if you don't believe it, you cannot be there for your daughter on top of that.
Keep posting here, and we'll do our best to help you cheer up.