I work for a multi-national company too (The equivalent of Walmart) and I can see how badly the depressive phases affect my work. I tend to have no concentration span, regardless of which phase I'm in (Mostly depressive) and don't get a heck of a lot of work done. E.g. it is 14:15 here now, and I've sure has hell got enough work to keep me busy, but I'm here.

I used to just close my eyes, and not move until my alarm went off the next morning. Now I need to take Benzo's to go to sleep, which I only take when I get into bed, which in turn I only do when I'm tired - recently it's been late.
Then when I'm going thro my depressive phases, I tend to sleep an awful lot, always feel tired, sleep in my car during lunch breaks, fall asleep at 8PM at home, snooze for most of the weekend...