up to one’s neck

up to (one's) neck in (something)

Having too much of something; overwhelmed by an excessive amount of something. I'm still unpacking my new house, so I'm just up to my neck in boxes. If any of my guys get hurt at the construction site, I'll be up to my neck in paperwork. There's no way I can take a vacation right now, I'm up to my eyes in work at the moment!
See also: neck, up
Farlex Dictionary of Idioms.

up to one’s neck

mod. filled up with something. I am up to my neck in other people’s grief and anguish.
See also: neck, up
McGraw-Hill's Dictionary of American Slang and Colloquial Expressions
See also:
  • be strong on (something)
  • address (one's) comments to (someone or something)
  • address comments or remarks to
  • address (one's) remarks to (someone or something)
  • be in it for
  • a run on (something)
  • (something) is over (one's) head
  • a rush on (something)
  • at the point of (doing something)
  • be dying for (something)