Confess to upsetting the maid starting tomorrow (5)
I believe the answer is:
admit
'confess to' is the definition.
(I've seen this before)
'upsetting the maid starting tomorrow' is the wordplay.
'upsetting' indicates an anagram.
'starting' says to take the initial letters.
The initial letter of 'tomorrow' is 't'.
'maid' with letters rearranged gives 'admi'.
'admi'+'t'='ADMIT'
(Other definitions for admit that I've seen before include "receive" , "permit to come in" , "Provide student with place" , "Confess; allow in" , "Fess up" .)