For my part, I never have had an inkling of whether I might have caught the thing. No known contacts; no symptoms; a low level (typical of me) of rubbing shoulders with strangers and not-so-strangers alike; crucially, this also applies to the sole person I have Bubbled with, reducing the chance of it being an utterly Silent Surprise.
I never asked for an antigen test (i.e. "am I currently infected") because it was never a topical issue. Even when the lateral-flow things started to be for 'anyone who wanted one' rather than in the prior (increasingly expanded) ring-fence of greatest need vs. supply. I
would have considered an antibody test ("have I previously been infected") if offered, just to get a reasonable (within accuracy limitations) idea of if I might have been exposed.
Too late to do the latter now, probably, except to validate the vaccination.
Possibly with the right kind of sensitivity/discernment it could pick out a slightly different spike-detection from the one I'm innoculated against, but that's not going to be a "two blue lines" test.
Right now, then, I'm choosing to believe the 'hit' I got was just from dealing with the sudden ChAdOx1 intrusion, not an unknowing prior familiarity with the added nCoV-19 'spikes'. We'll have to see what happens in July when my body, definitely primed by then, gets another bash at another dose flushed into it. (Assuming I don't get recruited to trial dissimilar-jabs, though that's not likely.)
And "what I feel like" isn't necessarily "how well my body deals with it". It might well be the inverse, in fact.
(
https://xkcd.com/2443/)
BTW: The delayed-sore arm is still
very sore, but I've lost (or gotten used to?) almost all the flu-like aches and temperature issues.