Here is an example of what happened to me today:

I slightly insulted/pissed of a girl via text. I know the next morning after she wakes up SHE will apologize to me and be more attached. And even if she isn't, I can do better.

Still, now that she is sleeping I still have to do some work and I am kind of nervous, even though I am in a win-win situation. There is literally no way I can lose in this. How can I calm myself down completely so I can work properly?

I have tried to do 20 pushups every 20 minutes or so, that helps for a short while but I still can't concentrate as well as I want to.

So what are your tipps to simply not giving a fuck?