(Cover) - EN Showbiz - Pink feels "bummed out" to miss a performance for President Obama tomorrow.

The star is recovering from stomach flu and painful ulcers and had to turn down the opportunity to sing for the US head of state.

The 32-year-old wrote on her Twitter profile that she feels like she has been disappointing people because of her health problems.

":( I'm so bummed i can't perform for The President of the United States this Wed night," she tweeted. "so now I've let down my daughter and the President. wow. great week (sic)."

Pink's first child Willow Sage celebrated her first birthday last Sunday and the So What star expressed her annoyance about not being able to fully join the party.

However, the little girl got spoiled as she was treated to presents and cake at the hospital where Pink was being looked after.

"Thanks family 4 bringing my lil girls party to the hospital all weekend for me (sic)" Pink wrote before adding a day later: "i think i got a bag of cheetos and a teddy bear for my 1st birthday. However, Willow just got a Gucci dress and a custom rocking chair for her birthday. lucky little girl (sic)." (C) Cover Media