The "Problem" hitmaker began feeling unwell last week and took to Twitter to share the news.
"Sacramento, I'm so so so so sorry that I'm unable to perform for you. I'm just too sick... I never want to disappoint you. Rescheduling the show for Thursday and I really hope I can make it up to you then... & I love you so so much," she wrote.
When her condition got progressively worse, she updated fans over the weekend.
"Sick sick sick. Everything hurts... Resting / tryna (trying to) get better for tomorrow," she had written.