Has anyone felt cognitive decline due to meds so badly it feels like they can't perform their job?

I work at a board game store and part of our business is 2nd hand board games. Often times these come with expansions in the base game box which requires me to sort through and split the expansion components from the base game as well as do a general double check that the games are complete. Lately i feel like im really struggling with this and making mistakes (as proven by customers receiving incorrect/incomplete games). This sorting process used to provide me with a sort of therapy and now i simply dread and hate it.

Has anyone else experienced something similar? I am definitely going to see the psychiatrist soon and will bring it up with him. Currently I am only on Sodium Valproate and nothing else. In the past I have been on multiple meds and definitely felt the fog but this feels different, more of a slow and even decline which is more scary. I am a 35 year old male.