I am very sorry for your losses. Nothing can bring people back.
Math especially requires learning from the bottom up. Most concepts require an understanding of one or more basic concepts, and as you say, just keeps building.
Khan academy is probably the best and least monetized site I know of. MIT Open Course Ware is also good.
There are so many styles, patterns, and colors of caps under the very wide term of flat cap. I think the pretentious feeling is silly, and probably geographical. I have baseball hats, beanies, newsboys, whatever. It doesn’t have to be your thing, just a thing you have.
No. Sr. Grafo posted his own comics, then made comics in the replies to people. Shittywatercolor did as his name says to random comments in any thread.
So sorry, dear one. I have had many physical ticks, habits, addictions. Only one has been terribly damaging. I haven’t been able to stop that one, but I have been able to stop some. My technique has been replacing a harmful one with one less harmful. I’m not sure I have specific advice other than to talk to a psychiatrist. In the most stressful time of my life, I managed to stop chewing my nails by taking anti anxiety meds. When life evened out, I didn’t need them anymore (now I am meticulous about nail clipping and filing). I stopped picking at my feet when I got a foot rasp. Using it after baths with just my feet in the tub it felt like I got what I needed without hurting myself. Keep working, but professional help is best.
Gen X had to learn learn how a computer works at a pretty basic level just to be able to use one. I took basic computer skills and programming for the TI 994a in elementary school. Then another hardware/software class around 5th grade. It was pretty easy to troubleshoot anything hardware or software until the mid 2000s.