For the most part my work hasn't been heavily effected, because my symptoms tend to be more physical. In the first couple of days, I am tierd and lethargic with light brain fog, so I'm slower in those couple of days.
But recently (in the last 2 or 3 months) I've had a couple of doozies, where the cognative aspect has been very strong, although fortunately relatively short. In those days, I'm right out of it. I understand now how some of you can really be suffereing, if the congative is strong and long!