Owing to having gone in above one's head? (4,2,4)

'above one's head?' is the definition.
I don't know anything about this answer so I can't tell whether it can be defined by this definition.

'owing to having gone' is the wordplay.
'owing' becomes 'in debt'.
'to' means one lot of letters go next to another (I've seen this in other clues).
'having gone' becomes 'deep' (I am not sure about this - if you are sure you should believe this answer much more).
'indebt' put after 'deep' is 'DEEP IN DEBT'.

'in' acts as a link.

Can you help me to learn more?