The super-obsession of Justin Bieber and his songs; Knowing the words to all of Justin's songs and everything about him; The impression of having stayed up all night just listening to his songs and waking up in the morning feeling like you're sick.
Girl A: *moans*
Girl B: What's wrong?
Girl A: I stayed up all night listening to Justin Bieber's songs and making a webpage for him.
Girl B: Oh...so you have bieberfever, am I right?
Girl A: Hell yeah!