I expect he's probably bruised his foot jumping down onto something sharp or hard in the garden.
I thought I was the neurotic one lol
The first sign of anything I'm on the phone to my Ex ( vet nurse) I feel foolish for fussing so much but I would never forgive myself if they suffered because of my negligence.
Peanut once uncharacteristically pestered me for cuddles for several days . One night I realised he was panting and his pulse was sky high sure enough he had a very high temp. Rushed him in and he had a bad infection .I still feel very guilty that his Dad didn't recognise he was unwell for so long