"I've found it tougher than I ever thought I would," he said during a special edition of his Late Late Show.
"You feel so out of control," he said. "It feels so beyond our comprehension, all of it, that I've found I get sort of overwhelmed with sadness in it all."
He broadcast live from his garage in LA and was joined via live stream by stars like Billie Eilish, Dua Lipa and BTS.
The British star, whose US talk show has been on hiatus due to the virus, told viewers his anxiety came about "when I allowed myself to think about my family back home in England, or my friends, or the people I love".
He continued: "It's OK to feel anxious. The best thing we can all do is kind of breathe through that and put our minds in a positive place."
Corden also suggested we ask ourselves: "What can I do to help someone else who might be feeling like this? And just me talking to you tonight has made me feel a bit lighter."
He said the purpose of Homefest: A Late Late Show Special was "to bring some joy and some music into your home at what is without a question one of the strangest and scariest moments in all our lives".
He added: "We absolutely will get through this."
During the broadcast, Eilish and brother and producer Finneas O'Connell performed Everything I Wanted, while Dua Lipa sang her hit single Don't Start Now from her London flat.
Echoing the thoughts of many fellow parents during lockdown, John Legend said being quarantined had given him a greater appreciation of the job teachers do. He and wife Chrissy Teigen have two young children.
Actor Will Ferrell also appeared, while opera star Andrea Bocelli paid tribute to his home country, Italy, and performed his song Con Te Partiro.
The broadcast came a night after a televised charity special hosted by Sir Elton John from his living room.
The iHeart Living Room Concert For America, which featured Eilish, Dave Grohl and Mariah Carey, has raised $8m (£6.4m) for Feeding America and the First Responders Children's Foundation, according to Variety.