I never forgot anything pre-diagnosis. I was super sharp, never missed a trick unless I was out of my gourd. But I was a maniac and when I crashed into the wall, people were afraid of me. Thus......I'm not sure cognitive function is attributed to the illness. I don't believe memory is listed as a symptom of BP. When I started to take medication, I started to forget simple, but not major, stuff.......things like "what song was just on the radio". On the positive side, lithium seems to have made me goofier and less edgy and in my profession, being endearing is a big plus. One of my students last year wrote me a thank you note and said he'll miss my "classroom shenanigans". Another student said "legit, you're the funniest and most real teacher in the school, legit". Yup, she said "legit" twice. Legit. Anyway, while the the wide circle has plus and minus, being much less of an asshole has its benefits.

IMO - there could be a number of simpler things at work. Perhaps you have too much on your plate. Maybe you're not getting enough sleep or enough quality sleep. Check your diet as well. Or perhaps your mind just isn't engaged, especially at work. In my old job, my head went to mush because I was bored out my skull.