I am nearly twice your age. Pretty much everybody has been through a version of what you are experiencing. Two things you must know.

1: You had a relationship that was valuable enough to you that losing it hurt. That is special in itself, and you need to consider the good thing that you had. Seeing a concert is ephemeral, but you remember the music and performance positively. Think of the relationship this way, also.

2: Give yourself time to mourn. Mourning is natural, and it is a process, but there is an endpoint. Many have walked this path and come out on the other end.

You are young, and you will have many more experiences in your life. Some positive, some negative. But your life is far from over.

Take a day, go for a long walk at the beach or park or nature trail. Cry, weep, wail, knash your teeth. Then move on.