I got a flu in 93 or 94 that felt as if George Foreman had kicked my ass from the inside. We're talking pain. Couldn't comfortably sit up, stand or lie down. Non stop fever and chills for a week. I survived on Alka-Seltzer plus cold medicine every six hours. I don't remember anybody I knew seeing a doc for that kind of thing. Maybe in the upper or middle classes.
I've had brutal flus 3 times in my 75 years. I laugh at people who think they've had the flu when they get a bad cold. The 1957 one was no party. When my fever broke, my bed was soaked and it took me a half hour to call my mother.
I had something very similar in 2013. I learned my lesson. Every since then I took my flu shot and have been fine since. And yes, I also have all of my other vaccines updated too.