From Longman Dictionary of Contemporary Englishbe in (too) deepbe in (too) deepinformalSERIOUS SITUATION to be very involved in a situation, especially so that it causes you problems → deep
Examples from the Corpus
be in (too) deep• I'm in too deep to get out of the business now.• The advertising industry was in deep recession.• The planet and the country are in deep s-- -.• The pathway was in deep shadow.• Tonight, the parents are in deep shock.• He warned management during training camp that the team would be in deep trouble if either he or Johnson suffered injuries.• Our governments are in deep trouble today.• If everyone except Fifi and Manuel shows up at the compound, the lovers will be in deep trouble.• Some of the discoveries were in deep water. 