No, nothing physical or traumatic. The 'one day' was a figure of speech, it was the post high-school -> college transition. I became too lazy before, college through a lot more stuff at once, and it was more about very abstract principles rather than usual objects. You don't use a function, you imagine all functions on highly dimensional spaces .. also psychologically I wasn't used being behind the pack, stress and negative emotion will make you trip faster.

There's also something about how college material is presented maybe, it's a bit obfuscated behind notations. Or maybe that's just me not being in sync with high level thinking anymore. As a kid I loved all weird notations without feeling lost.