I'm kinda pissed and impatient with people who say they are sorry but did what they were sorry for the the next day (you know I'm talking about you). It's like they are not sincerely apologizing for making someone angry, for screwing up and for not doing what they should be doing.
So do me a favour by apologizing sincerely, admiting that it is your mistake and offering to make it right.
Do it now!