While I agree with you that a hearing test is no the worst thing one can do, ironically, some parts were so loud that I had to remove my headphones.

That could actually support the same conclusion. It's a common misconception that hearing loss is general quieting across the board. What's more common is to have selective loss in some frequency ranges. That could encourage you to turn up the volume to ear those ranges better, which then might result in sounds in other range being uncomfortably loud.

Edit: more likely though is probably your speakers or something losing frequencies though!

Excuse the unintentional typo pun! And the missed 's' on 'ranges'. And the double 'though' in the edit. For the first two at least I can blame low batteries in my wireless keyboard...