Special appointment. Outside, lose return! So depressed (8) (8)
I believe the answer is:
desolate
'depressed 8' is the definition.
'desolate' can be an answer for 'depressed' (thesaurus). I'm not sure about the '8' bit.
'special appointment outside lose return' is the wordplay.
'special appointment' becomes 'date' (synonyms. I am not sure about the 'special' bit.).
'outside' indicates putting letters inside.
'return' is a reversal indicator.
'lose' back-to-front is 'esol'.
'date' placed around 'esol' is 'DESOLATE'.
'so' acts as a link.
Can you help me to learn more?
(Other definitions for desolate that I've seen before include "Dale's toe (anag.)" , "'Deserted, wretched (8)'" , "Utterly wretched" , "'Bleak, bare (8)'" , "upset" .)