I’m firmly fixed in my place of rest (8)
I believe the answer is:
imbedded
'my place of rest' is the definition.
I can't judge whether this defines the answer.
'i'm firmly fixed' is the wordplay.
'firmly fixed' becomes 'bedded' (I can't explain this - if you can you should believe this answer much more).
'im'+'bedded'='IMBEDDED'
'in' acts as a link.
Can you help me to learn more?
(Other definitions for imbedded that I've seen before include "Deeply fixed; deb did me (anag.)" , "Firmly implanted" .)