This pet suffering? Worst possible thing (3,4)

I believe the answer is:

the pits

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'worst possible thing' is the definition.
'the pits' can be an answer for 'worst' (I've seen this before). I am not sure about the 'possible thing' bit.

'this pet suffering?' is the wordplay.
'suffering?' indicates anagramming the letters.
'this'+'pet'='thispet'
'thispet' anagrammed gives 'THE PITS'.

Can you help me to learn more?

(Other definitions for the pits that I've seen before include "terrible situation" , "pants" , "A very bad situation (informal)" , "place to service a car?" , "hell!" .)

I've seen this clue in The Times.

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