Pink wrote in the image's caption: "Maybe it's cause my mom was an ER nurse all my life- but throw me in a gown and a hook me up to an IV- and I'm a happy girl. Stomach flu sucks but morphine doesn't."
The star later clarified that she was in fact joking about being given morphine and also expressed gratitude for her fans' support.
"Thanks for all the get well wishes. And no-they don't give morphine for flu. I might have ulcers again. Because I care too much. It's a gift," Pink quipped.
Pink's mother Judith Moore notably worked as a nurse in their hometown of Doylestown, PA throughout the singer's childhood.
The star recently revealed that she has cut back on her drinking and smoking since giving birth to daughter Willow Sage Hart last year.
Pink is currently working on her sixth studio album.
Ray's Top 5 of the Week (September 22 - September 28)
5. Capital Cities - Safe & Sound
4. Miley Cyrus - Wrecking Ball
3. Katy Perry featuring Juicy J - Dark Horse
2. Lorde - Team
1. Lady Gaga - Applause