Thoughts about my bestfriend.

I am bi. Everyone knows it at school and I'm not very shy about it. I've known my best friend for 5 years now, and for 4 of them I've been madly in love with him. I want him bad. I want to hold him, kiss him...other things...but I can't. He is straight, and constantly plays with my heart whenever I see him. My heart races when I give him a "friendly hug. And cries when it is over. How do I expell these feelings of intense devotion from my mind? I can't tell him because he is straight...but if I don't expell these thoughts soon I fear I might do something very wrong to him. Please help me. I don't want to hurt him.