@simbobs you are certainly not an imposter and these things could happen to any of our DC. Really sorry both yours are struggling at the moment. Hope your DS gets on the case (or your DH if necessary). I think sometimes at that age they are not always able to quite put their finger on what's wrong if they're struggling.
@RampantIvy sorry to hear your DD has been struggling. It's always a very full-on term not least because it's long and pressured, whether you're in school or university.
And really sorry to hear your DS has been unwell @icanbewhatiwant and hoping his (nad this friend's) tests come back negative.
DS was really ill for a fortnight with some type of mega throat infection but being him he didn't do a PCR. I don't think he was out and about much if at all in that timeframe as he felt too ill. Couldn't easily swallow anything. He's much better now but catching up on assignment work (he has several pieces of work due this coming week).