Kate Moss had been devastated when she learned her personal assistant is leaving. The 34-year-old supermodel was distraught when her PA Fiona Young, who she described as her "rock," resigned.

Young is leaving at the end of the month to have a baby. She has reportedly told Moss that she may not return.

A source said, "Kate got completely drunk and started crying about Fiona leaving. This woman is like a sister to her - she has held her life together through thick and thin. Kate is beside herself."

The fashion model had the PA for seven years. She had been her closest confidant and best friend.

The source continued, "Kate has been saying her life will spin out of control when Fiona leaves and she does not know how she will cope."

"Her partner Jamie Hince is on tour with The Kills, her mother Linda is renovating her home and her long term nanny Jade Davidson quit in December. Now Fiona, the rock of her life, is leaving."

Fiona, aside from being on her payroll, had been Moss' closest friend, even closer than her partner. The source says, "That trust is a very delicate thing."