Exactly my attitude. Luckily I have been fine after shows so far (vaccine working I guess) and like yourself am very conscious of how I am feeling in the days following. I too would take a test if I felt any symptoms.
Still wear mine on public transport and at the supermarket. Always leave the house with one
At gigs though, I tend not to as I regard those as at your own risk environments and people generally do not wear them. I would be in favour of covid passports or test results required for entry though...