gimme my moment

The weekend is over... I could (probably should) start the week off with the right attitude. Call me childish, selfish, whatever, but sometimes I just wanna be bitter! I just want to be annoyed, and I want to deal with it when I am good and ready, not when someone else deems it appropriate.
So often I feel like I am not allowed to be something, because its not 'right.' Well, we are human beings, we are NOT 'right' all the time, sometimes we stumble, sometimes we just want to sit and stew in our misery, whether self-inflicted or not.
I know that I cannot indefinitely wallow in my self pity - that's not what I am getting at... its just... is it really so bad to wallow for just a little bit? Can't I have this moment of unsettledness, a relatively insignificant speck in time?
The other day I was pretty frustrated about something, and I was talking to someone who really understands me and knows me well - as well as anyone. I said something that was downright mean actually. A moment of weakness. Rather than support for my feelings, and a genuine desire to help me work through my frustration, I received a lecture on how to not say things like that. I'm sorry, but no shit...
Maybe what I am really mad at sometimes is the fact that its sooooo terrible to be mad, even for a moment... And rather than feeling that I get the empathy I seek, I feel even more ashamed, and left with more "things about me that I need to work on."