Multiple sources tell PEOPLE that the Grammy-winning performer, 43, missed several episodes of her talk show, The Kelly Clarkson Show, earlier this year largely due to her ex-husband Brandon Blackstock 's illness.

"It's been exhausting and so sad," a source told Page Six of Clarkson, who took time off her show to care for her ex-husband Brandon Blackstock.

Clarkson’s last Vegas show was on Saturday, Aug. 2 and she was set to resume her Studio Sessions performances on Friday, Aug. 8 as the first of four more shows in August at the Colosseum at Caesars Palace. The residency is set to resume in November.