Well, Islam is an efficient religion. Thus all you have to do is to follow it diligently. And, never act as an emotional fool. As nothing is permanent in life. So all you need is to remind yourself of this. People come and go. And those who have to stay, they stay. And those who don’t, they will never. No matter how hard you try. So, in our text, it is written. The love of Allah is the truest of all. Furthermore, what is there for you will always be there. But, a person who was once there in your life. And now they are no more. Then diverting your mind is the best thing. Also, I am not saying you should forget about that person in a day. But, yes, indeed you can try. Once you keep yourself busy in Namaz and dua. Then Inshallah, you will see the change gradually. Also, dua had immense power. Once Allah knows what you want. Thus, inshallah, you will have his help. Moreover, you need to get rid of things, which reminds you of them often. And, when you start doing that. Then Inshallah, there will come the point that when letting them go. It will get effortless. And Inshallahit will happen. And, all you need is a little effort from your side.