I find I normally have to take *off* warm clothing before getting on my bicycle, since as it's not electric the cycling process involves vigorous activity! I did eleven miles yesterday having made the conscious decision not to put on my neck-gaiter (which I am currently wearing for walks instead), and found it was the right choice; I was wearing a cardigan over a sleeveless jumper so that I could unzip my clothing if necessary, but managed not to overheat for once. My toes got extremely cold, especially the right foot which I am in the habit of using to stand on at traffic-lights, and were too numb to walk on when I returned, but to my surprise my ears, which were completely uncovered, were fine. I suppose all the body heat must have been venting upwards -- I wouldn't have cared to do it in three pairs of trousers, though. As it was my bare knees got a little chilly...

Yes, anyone with active Covid antibodies tends to have a worse reaction to vaccination (and the second vaccination is worse even in those who haven't had it, for the same reason ). But the majority of people I've heard from seem to have an unpleasant side-effect on top of the usual sore arm, up to and including vomiting and 24 hours of high fever, so you seem to have been one of the relatively lucky ones.