I came across this forum because I recently have been having some medical issues that started last year. Still trying to figure out the source of it, since it seems like doctors don't take you seriously nowadays or throw drugs at you and send you a bill.
Anyways, my point is I try not to take OTC medications these days due to the above. I have had migraines since I was about 9 years old (I'm 27 now) so prescription migraine medicine and OTC pain relievers have generally been common for me. Though.. suddenly started taking tylenol more last month because I had a 3 week long headache and worse migraines peppered into that time frame. Saw a neurologist that was pretty useless, gave me pills and had to express more concern for my sudden appearance of other neurological issues over the course of this year. As far as I'm aware I have never had covid, for reference, and managed to get an MRI and EEG order (I have tremors, cognitive and balance issues as of around Feb./Mar. 21). Short story long here, I have had this very feeling first with Advil after not taking it for a year (longer story) and after I've used Excedrin tension headache (Acetaminophen and caffeine). Caffeine is in my daily routine so that's nothing unusual for me. Though, I wasn't even thinking about the tylenol after I took it around 1030a at work, as my day progressed, I felt weak, out of it and an uneasy stomach. When I have a headache I usually attribute those feelings to those of the postdromal nature, like after a migraine. However, for the second time so far, I had an internal "vibration" feeling. First time I had that, had no tylenol involved. So I checked my BP after I got home. My BP is elevated as well as I had 2 irregular heartbeats detected. Which is new.
Following up with research, for some people it can cause an increase in BP which can cause the symptoms listed above. My mother had high BP so I have started to monitor mine following a spontaneous fainting episode back in about... June I believe? I wouldn't go so far as to completely discredit the OP on this, like doctors do lowkey, which has lead to people having to stop short of getting upset because they don't want to listen to you for more than 5mins and charge you for nothing. I don't think it's placebo. It might be worth writing down the particular episodes post tylenol use and what symptoms you experience. Maybe you just need a different OTC pain reliever. As I write this, I still feel sick and it's well out of my system by now seeing as it's currently 6pm and I took it at 1030a (3hr half life and 6hr pain relief total). Just my thoughts from the perspective of my own weird health issues. You're not alone. You'd be amazed what the 1% of people experience with seemingly normal things.