I miss my best friend and feel depressed. What to do?

Hi doctor,

I am an 18-year-old boy. Last year, I made a best friend. He was like my second half. He used to share each and everything with me. A few months back, I saw him with his ex-girlfriend, and they are in a relationship now. He never told me that. She lives near my home, and my friend always drops her home, but whenever I asked him to come to my place, he used to tell me that it was too far away. We had a major fight without any violence, and we both stopped talking. Then I started realizing that I liked him so much. I miss him as he used to hold my hand in public places always. I started remaining sad the whole day. I was depressed and tried to commit suicide. After that, I sometimes express all my warm feelings to anyone on chat, and after a few minutes, I regret it. I feel like there are two people inside me. At first, I thought that it was a split personality disorder, but I do not have memory loss. Please help me. What should I do? I hate his girlfriend. But I am not sure whether I love my friend or not. Sometimes, I feel like I love him, and after a few minutes, it is like just friendship. Am I gay? But I have a crush on girls, also. I think I am attracted to both boys and girls. I am totally confused. Kindly help. Thank you.