Unhappy because the gin is nearly finished? (3,2,7)

'nearly finished?' is the definition.
I know nothing about this answer so I can't judge whether this works.

'unhappy because the gin is' is the wordplay.
I cannot quite understand how this works, but
'unhappy' could be 'low' and 'low' is found within the answer.
'the' could be 't' (the is pronounced as a 't' sound in some dialects) and 't' is found within the answer.
'is' is found in the answer.
This explanation may well be incorrect...

Can you help me to learn more?