GIMME A HAND, BROS!

So long story short, long term girlfriend is getting ready to leave me, 95% Sure of it, she's showing all signs that she's done with me

How do I mentally prep for this shitstorm that's about to happen?

We share all the same friends

Our families are friends

We work in the same building

We live together

It's coming, I can feel it, how do I handle it? How would YOU prep for it?