(CNN) -- Miley Cyrus could be in celebrity sick bay for another three weeks because of an "extreme allergic reaction" to an antibiotic, her representative said Thursday.
Her illness interrupted her "Bangerz" tour when she was admitted to a Kansas City hospital Tuesday.
Cyrus, 21, tweeted to fans Thursday morning that she is "over the hospital," along with a photo of her lying in bed. She added: "can't quit crying i wanna go back on tour. im meant to be onstage performing for y'all ... not laying in a hospital bed."
She canceled a show in Charlotte, North Carolina, last week because of what was reported to be a flu-like illness. Tuesday's Kansas City and Wednesday's St. Louis shows were also canceled.
The statement sent to CNN by Cyrus' representative did not specifically say it, but it implied that her upcoming shows over the next week -- including Nashville; Louisville, Kentucky; Philadelphia; Uniondale, New York; and Connecticut -- would be off.
"Miley was suffering from a sinus infection during her tour in N.C. a week ago. She was prescribed the antibiotic Cephalexin which she has now suffered an extreme allergic reaction to," the statement said. "This type of extreme reaction can last from five to 27 days in these types of cases.
"She will remain hospitalized and is under a doctor's care until we see some improvement in her condition and is asking for your compassion and privacy at this time. Miley is devastated about missing shows and possibly disappointing her fans."
CNN's Carolyn Sung contributed to this report.