Losing my brother.

I know that it may be wrong to post this on here. But this counts as love to me. Therefore il post it. 
I love my brother. Im 16 he's 20 Growing up we were always close. He's my best friend. I'd give up my life for him. He's always getting into trouble. All sorts. He's been escorted home by the police on numerous occasions. He's into drugs and drinking and everything. I always protected him. He would come home a fall straight onto the floor and I would be the one trying to get him on his feet. Giving him water. Anything. But ever since I turned 14 he's changed. He's more distant than ever. He never spends time with me. In fact now he doesn't even talk to me.  I barely ever see him around. I have minor depression. I was diagnosed 6 months ago. I met this boy last month. We went to his house and I got drunk and lost my v card to him. I've never regret anything so much in my life. To this day I cry myself to sleep just thinking about it. I really want to talk to my brother but I don't know how to. He's so mean to me. He slams the door in my face. Walks right past me and doesn't even look at me. What have I done to him? Three months ago it was my birthday and at midnight he came into my room and kissed me on the forehead and walked out. I was pretending to be asleep. I'm so confused. Does he love me or not? What do I do? I need him in my life. All my attempts fail. Someone please help