swim in (something) up to (someone's) neck

Translations
быть по уши в (чём-то)
I'm swimming in paperwork up to my neck.
Я по уши в бумажной работе.
Definitions
To be deeply involved or heavily occupied with something, often to the point of being overwhelmed. For example, 'I'm swimming in work up to my neck' means having so much work that it feels almost unmanageable.