A Phoebe Bridgers Stan. (Can easily be used in context to describe a really sad person as well.) You probably listen to her music daily, not even giving yourself a chance to be happy in the mornings.
As uttered by Rowan Atkinson in the film 'JohnnyEnglish' after accidentally injecting himself with a paralysing serum. A sound made in response to total incomprehension to a statement or series of statements or questions directed at that person immediately beforehand.
After a complicated lecture by a physics teacher, the question is asked "What is x?" The response to which is "Phlabb?"