too bad
regrettable
ruesome
regrettingly
fear
bewail
lament
deplore
bemoan
live to regret
guilt
pity
self-reproach
remorse
apology
compunction
shame
regretlessness
regrettableness
regret
regretfully
regretter
whip the cat
sayang
rue the day
apologize
regretting
regretfulness
repent
repine
regretful
ochanee
wear sackcloth and ashes
lamenting
lamentably
desire
I'm afraid so
Ichabod
sorriness
unhappily
misgave
mean
no such luck
could have, would have, should have
penitence
repentance
overgave
seem like a good idea at the time
prick
penance