Elated with care, in a bed, though not thinking clearly (6-6)
I believe the answer is:
Here is my best explanation:
'not thinking clearly' is the definition.
'elated with care in' is the subsidiary indication.
'elated with' becomes 'absented' (I can't explain this - if you can you should give a lot more credence to this answer).
'care' becomes 'mind'.
'in' indicates putting letters inside.
'absented' placed around 'mind' is 'absentminded'.
'a bed though' is the link.
This may not be correct. Some or all of it may be part of another bit of the clue.
(Other definitions for absent-minded that I've seen before include "Liable to inattentiveness", "Preoccupied U forgetful", "Scatty", "Prone to forgetfulness", "Wandering", "Given to woolgathering", "Forgetful, inattentive", "Vague and forgetful", "Scatterbrained" and "Inattentive".)