What are the rules here?

So seriously what are the rules here? I feel like a complete fish out of water right now. I was in a relationship for the last 11 years and didn't start dating until my 20's. Now that I'm single again how does this work?
And I don't mean the way I see some... I feel like sad,y some of my peer group that become suddenly single in their late 30's /early 40's are on some sort of hunt. Hurr, hurry, fast, fast, fast upgrade the ex, experiment with sex. Start again...
I'm still trying to fix me. I feel like until I'm good with me, I'm no good to anyone else.  And I keep going back to I couldn't make him happy how could I possibly make a hot version of him happy.  Especially when the hot version of him rather be with someone at least a decade younger. And I have a little person, who will always come first. Which at my core is why I think my marriage failed. My ex husband became number two.
And I'm honest, brutally so and shy. I really feel most comfortable talking to people (men) with a liquid courage but to be honest at 41 - sad. And as a Mom - tragic.
So here I am trying not to over think, not be a clique, just be.
But like everyone else wanting it all to make a little sense... But can it?
We are talking about relationships here...

So I guess here I am waiting...