Sounds like brain fog. Speaking as a fellow sufferer of anxiety (health anxiety included), I know how it is see something that seems wrong with you and try to pin a cause onto it. Are you being social? Keeping up with sleep, food, exercise? I know those are overstated but it sounds like you're having some brain fog. The more you focus in on the fog the more it may seem pronounced, as brain fog is highly influenced by stress. I've suffered from some myself and have felt kind of tuned out for a while. A large part of it for me has been from the shock of different life changes and the endless stress of work and relationships. The fog in that situation doesn't get a chance to subside because the body is trying to get through sustained stress with little damage.

It could also be from imbalances of vitamins like vitamin d or iron. Just to be clear, I highly doubt it was from the burning cable. It's definitely not good for you, but people smoke cigarettes and breathe road fumes for decades without losing the mental capacity you're describing here. Funky stuff happens when we look back on our past selves too, I feel like it's hard to make a fair comparison to yourself at any prior point when you factor in a lot of things that happen in-between. I don't doubt what you've been experiencing though. Sounds crappy. I hope you give yourself a chance to consider all of the possibilities and be easier on yourself for not functioning at 100% right now -- it doesn't mean it's forever or that it means something big, it could just be your capacity right now.