I am separated from my AH as well. I would say that "faking it til you make it" may be the best way to go, say, at work, but for me, at least, faking it isn't an option. I've had to instead choose to at least accept the way I'm feeling at any given point & just sort of...use the tools I have not to force myself to feel differently, but to ride out the feeling I'm in. Talk to someone you trust. Watch a sad movie for a while. Go to the gym. Have a glass of wine.
The one thing I WON'T do is try to contact my AH, because I know that that will only perpetuate the cycle. And, I can't trust what he says anymore, so what would be the point?
As healthy as it is to try & regain your own life, it's just as healthy to pause when it feels overwhelming & jsut let yourself be where you ARE. You may not be happy, confident or "over it" right away, & that's OK too. As long as you recognize that another relationship is not going to solve the problem of your AH, then you won't go seeking someone to fill that "void"...date someone else for THEM, not because of the person you're "replacing"...