My almost 4 month old will not sleep for long periods of time like he was couple days ago

Tamara • Mommy to my 2 beautiful baby boys, Nathan Louis💙 born August 12, 2017 and Parker Joseph May 6, 2019❤️ My whole world😍

Not even during the day. It’s a couple hours then he wakes up and cat naps. He’s sick 😞 had fever yesterday and stuffed up nose. anyone else have any advice ?