I can assure you, after almost 35 years of wearing aids (never CI tho), I get hearing-overload fatigue OFTEN! Maybe it’s a day with lots of social activity - BBQ, party, etc., or a long trip to the mall, or just a rambunctious movie, or being in a restaurant with MUSIC playing while I’m trying to read lips.
The brain can only digest and process SO many things at a time. Hearing fatigue is TOTALLY common, and the best way to keep it manageable is to set aside time during the day - maybe just 20 min 2-3 times - when you go in a quiet room or take the aids out and just let yourself decompress.
I know that my cinderblock ears are a HUGE liability during the night when my aids are out, but I THANK GOD every night for being deaf as my bedpost and not having anything but the 24x7 tinnitus to lull me to sleep.