Because I've entirely lost it.
It's not a general cognitive issue. I can still do my job properly, complete the FT crossword and answer a few questions on Only Connect. But little day to day things, they escape me. I'm forever losing keys, phone, umbrellas, sometimes even big things (a cordless drill eg, still don't know where that went - I even "lost" my bike for a week recently went somewhere on it, forgot I was on it it, got an uber home, didn't need it again for a few days, went to the shed and couldn't remember taking it out). If I put something down I won't remember where it is, unless it's in a place I always put it. If something takes my attention in the meantime, I'm fucked.
Has anyone else had this and overcome it? I feel like a flakey mess and I'm wasting loads of time retracing my steps looking for things.