Busy period — Mike’s forgotten about self-esteem (2,3,2)
I believe the answer is:
on the go
'busy' is the definition.
(similar in meaning)
'period mike's forgotten about self-esteem' is the wordplay.
I cannot quite see how this works, but
'period' could be 'th' (Th is an example) and 'th' is found within the answer.
'about' could be 'on' (as in a book 'on' a certain topic) and 'on' is located in the answer.
'self' could be 'ego' (synonyms) and 'ego' is located in the answer.
This accounts for all the letters.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for on the go that I've seen before include "Moving -- active" , "Active and energetic" , "Active, in constant motion" , "Always busy" , "ready to start monopoly?" .)