How To Heal A Broken Heart?

Recently I've been In love with my best friend, he did have a gf but he said he liked me too, we did kiss here and there and did special stuff but recently I found out he never loved me in the beginning, he did love me like a sister and said he'd go out with me if he was single but that wasn't true... It's been three days since I've talked to him and I miss him sooooo much! I loved him and now he's gone :( Plz help me! Idk how to get my mind off of him :( thank u.