up to one's ears
Also, in up to one's eyes or eyeballs or neck. Deeply involved; also, oversupplied, surfeited. For example, I'm up to my ears in work, or He's in up to his eyes with the in-laws. This hyperbolic and slangy idiom implies one is flooded with something up to those organs. The first was first recorded in 1839; up to the eyes in 1778; to the eyeballs in 1911; to the neck in 1856.