Bewail

[Sarah]

To express deep sorrow for, as by wailing; to lament; to wailover.Hath widowed and unchilded many a one, Which to this hour bewail theinjury. Shak.

[Julene]

When you [fucked shit] up and feel so bad about it, to the point of disbelief that it truly happened to you that way. Almost as if you had a brief experience of [dissociative Identity disorder] due to the substance abuse at the time.
After a few days your mind may form clarity on the situation. Attempting to explain why you acted [out of sorts] just makes you look even more stupid than before.
You ask yourself what if? The weekend would have been perfect If I was in my clear rational mind as I am now.

[Julene]

Express great regret, sadness, or disappointment about (something)