When we use a comma, the latter part of the sentence elaborates the former.
In case of an exclamation, there is surprise.
In case of question mark, there is dissatisfaction.
A full stop is the fullest way of expression. Whatever has happened, has happened. Be easy and bring a full stop to it. (Because other ways of comma, exclamation and question mark never generated a response anyway.)
Why not try a full stop now?
Try a full stop.