I've been through a similar situation, OP - or, well, I guess I am in a similar situation. It kind of sucks, but maybe if you stop being so resentful of B you could really learn to love it? Or just do something to remind your friends of A, because they're probably still interested in it, just caught up in some shiny new thing. Hopefully if none of that works out, though, you're still good enough friends that different fandoms won't keep you apart. Good luck. *hugs*