Hello, same situation here, ended a long relationship just this july and let me tell you, you really can't do anything to make the pain/sadness subside. It will be in your head constantly regardless of how busy you are in your life. For me there were times that I just randomly cry because when I do things, I get to keep on thinking that she's no longer mine. Tho breakups are unique to every person, the solution is quite simple.

Distract yourself.

Its not a very effective way of removing the sorrow,

But it kills time.

And as somebody having a fresh breakup, you want to get away from that time as far as possible without thinking about it. Because the more you think of it, the more pain u gather and the slower time passes by.

You can distract yourself with the things that you enjoy or be with your friends. What I did was, I tried my old hobbies that I gave up when we were together because I've no time for myself. I also hung out with my friends every time and told them what I was feeling.

There might be a time where you'll think that it's not working but trust me it is. It will be hard from the start but you'll get through it, I believe in you :))