how worried should i be about bird flu?

i live in illinois and adopted a cat last friday. he was a stray and was only at the shelter for a couple weeks so there’s a chance he could’ve been around birds recently. he currently has a cold and his vet isn’t worried but i am(im a chronic overthinker/worrier). he doesn’t eat raw food and is strictly indoors but im just worried about the chances considering he was a stray for who knows how long