Sudden occasional drops in verbal and reading comprehension

recently I've been sufferings from occasional sudden drops in my ability to understand written or spoken word. It often comes alongside migraines or as a side affect of POTS related fatigue. It's doesn't seem like aphasia as I still understand language just fine, but comprehension requires some time, focus and attention.

any ideas what this could be? or if it is of concern?

(sorry if there are any spelling mistakes, currently being affected and it makes proofreading a bit difficult)