Well some of us dealt with extremes of whatever this (or that) was. Back when I first posted, I didn't get quite the same advice I give out.
But the back and forth thing you mention and being tired? You are not required to turn yourself into a total exhausted mess to try to deal with this. That's when NC will serve you.
Most articles I have read online advise going NC right after any break up. I guess it's up to each individual to decide whats best for them. But after you have had enough of the mind games, mixed messages, monster, lies, behavior and everything else? This is the one thing you can do for you.