This is very odd to me, actually. That he would suddenly cut you off like that means there must be a reason.

I can say I tend to be rather sensitive, sometimes overly sensitive, and especially as a child. That was one thing everyone always would tell me. "You're being too sensitive." I have cut people out of my life kind of like that. But I had reasons. I didn't necessariliy be forthcoming of those reasons exactly. One girl I was good friends with when I was having some pretty major delusions and she was part of my group of friends that just "played along." Instead of trying to see if maybe I needed help.

Anyway, a few years ago she found me on facebook and sent me a friend request and tried to be my friend. I told her that I no longer am interested in friends and I want to leave the past in the past, including all the people in it. I didn't feel the need to tell her that she had completely betrayed me and let me suffer while I was obviously having a mental health crisis.

So, maybe it's not something you're aware happened. Maybe it was something you said. You don't say how old you are, but bipolar wasn't being diagnosed in kids when I was a kid. But maybe you said something that really hit a nerve and he just wasn't able to get passed it, which is too bad. Maybe if he explained what happened you could have.

Or another thought is there could have been a rumor or maybe his parents didn't like you. Or something like that. It's hard to say for sure. It may be something you'll ever get to know.