Things aren't looking so good for Mariah Carey!

Just one week into her Las Vegas residency at The Colosseum at Caesars Palace and the singer was forced to cancel one of her shows due to a "nasty case of bronchitis," Us Weekly reported. The 45-year-old singer cancelled her Wednesday performance after doctors suggested that she be on "vocal rest."

Carey shared the news on Instagram, writing: "Hey guys..I've been fighting bronchitis for the past few days.. almost better but on mandatory vocal rest per doctor's orders. I'm so sorry to cancel tonight's show but I promise to make it up to you!!! Love you always, MC."

According to TMZ, the cancellation was announced last minute. Fans reportedly showed up to the venue to find a sign that read, "Tonight's performance has been cancelled and will not be rescheduled."

Her next Vegas performance is scheduled for Saturday, May 16, and Sunday, May, 17.

Carey's "#1 To Infinity" show includes performances from her 18 Billboard Hot 100 #1 hits, including "Hero," "Touch My Body," "We Belong Together" and "Vision of Love."