02/17/2012 at 03:50 PM EST
Nick Cannon is not a guy who slows down easily.
The 31-year-old star, who has been helming two radio shows out of New York, as well hosting America's Got Talent
in L.A. – not to mention being the father of twins! – has run himself ragged and didn't give himself time to recover from kidney failure
earlier this year, a source tells PEOPLE.
"He didn't give himself time out of hospital. It was getting worse," says the source close to Cannon. "Waking up that early in the morning and his travel schedule was grueling. He should have been recovered at this point."
On Friday, Cannon announced
that he's giving up his New York City radio hosting gig to focus on his health. He also revealed that he was hospitalized over the weekend for two blood clots found in his lungs.
"He's not doing so great," the source adds.
On Friday's show Cannon said he's not happy about having to stop doing his radio show, but he knows he'll be in trouble if he doesn't.
"I've been going hard for a little over two years and because of my recent health condition my doctor is like, 'Yo, you can't do that anymore.' I tried to fight 'em," he said. "I tried to be like, 'No, this is what I love.' And he was like, 'You're going to love it to death.' "
Cannon added, "I'm quite frustrated and sad, but It's definitely th best thing."
There is one thing that isn't causing him trouble, though: wife Mariah Carey
. "They are happy," says the source.
After Cannon was released from the hospital last month, he called Carey his "hero" for taking care of him.
"You guys don't see her at 3 o'clock in the morning, getting up in the middle of the night, fixing me soup when my kidneys ain't acting right. Mariah Carey does that," Cannon said onstage
before presenting his wife with the Entertainer Award at the 2012 BET Honors last month.