Miley Cyrus "can't quit crying" over missing part of her tour.

The 21-year-old is currently laid up in hospital after suffering a severe allergic reaction to some antibiotics on Tuesday. It means she had to cancel another one of her Bangerz Tour dates, which has left the star inconsolable.

"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 (sic)," she tweeted her followers.

Miley also used Instagram to post a picture from the Missouri hospital to her fans. In the snapshot, the We Can't Stop singer is tucked up in bed and the light is dimmed.

"over the hospital I miss #bangerztour #5amhospyselfie so sleeeeepy #medztime #wishicouldcuddlefloyd #whojinxedme (sic)," she captioned the selfie.

The star has been having a tough time recently after her beloved pet dog Floyd passed away earlier this month. She's also faced critics who have slammed her for cancelling shows, but Miley has been doing everything in her power to reassure her fans that she cares.

"humans can b so selfish. if any1 thinks id rather b layin n a hospital bed than doing what i love on stage theyre f**kin LAME. im miserable," she tweeted.

"I can't get a hold of my team because it is so early so I want to be the one to tell my fans especially the ones trekking to get there(tbc)

"the hospital is sayin i wont b released today therefore Im not going 2 make it 2 St Louis. Im so sorry but somethings are outta my control. (sic)"

Miley’s representative apparently confirmed to TMZ that she received a prescription for cephalexin after she was diagnosed with the respiratory issue in North Carolina last week.

However, the drug, which she had never taken before, is thought to have caused her throat to swell so that she could "barely talk".

Miley is scheduled to perform in Nashville tomorrow, but it's not clear if she will be able to attend.