One romantic gloomy about me (7)
I believe the answer is:
dreamer
'one romantic' is the definition.
(I've seen this before)
'gloomy about me' is the wordplay.
'gloomy' becomes 'drear' (I've seen this before).
'about' means one lot of letters goes inside another.
'drear' going around 'me' is 'DREAMER'.
(Other definitions for dreamer that I've seen before include "One who tends to live in an unreal world" , "Romantic" , "stargazer" , "One imagines" , ""You may say I'm a __" (John Lennon)" .)