According to TMZ, the 25-year-old has had some "complications" in hospital, including "extreme nausea and a high fever".
Lovato was rushed to Cedars-Sinai Medical Center last Thursday following a drug overdose.
A rep for the singer spoke out about her condition following the ordeal.
"Demi is awake and with her family who want to express thanks to everyone for the love, prayers and support," Nicole Perna said in a statement to USA TODAY.
"Some of the information being reported is incorrect and they respectfully ask for privacy and not speculation as her health and recovery is the most important thing right now."
Demi has battled substance abuse for years and recently celebrated her sixth year of sobriety.
Her new song Sober hinted at her possible relapse with the lyrics: "Mumma, I’m so sorry I’m not sober anymore/And daddy please forgive me for the drinks spilled on the floor."