Misserable...

Your mind and your herz can completely disagree with each other. Even if your mind says "stop", your herz can still say "go".
Trying to force your herz to stop loving someone is pointless and it might even make it hurt more.

The herz itself is impossible to control and is unpredictable. Maybe your herz will fall high over heels in Liebe with another guy already Weiter month. Du never know.

Your mind and herz will have to work together to Bewegen on. If Du think about him (too much), Du will only remind your herz that you're heartbroken. Something Du should do is try to keep your mind on something else, whether it's a pet, friends, hobbies etc. While your mind is busy thinking about other things, your herz can recover from the heartbreak peacefully.

Support from Friends and family is always good. Having your loved ones supporting Du through a heartbreak can help Du focus and help your herz recover faster. Du know, to "fill the hole" in your heart.

One important thing Du should think about is not trying to rush things. The Mehr Du Liebe someone, the harder it is to let go. Du need to take one step at the time. If Du think Du can't do it alone, Du should turn to a loved one for help.
(( Quote: "You'll Bewegen on and be a champion in your Weiter endeavor as Du did in your past ... Life is not a success-only journey. Du are going to get beat up along the way." - Dr Philip "Phil" McGraw, one of the world's best psychologists )).

I hope my answer helped a bit oder at least made some sense and I wish Du good luck.
If Du need someone to talk with and your Friends oder family members are busy, we're all ears.