I don't understand where your mum is coming from. On one hand, she says it's okay to be gay, but on the other hand, she condemns bisexual people.
You also claim to be gay, yet you also say you are bisexual, so I imagine you are not 100% sure who you are at this stage.
Good on you for coming out to your friends, and your mum. I never came out to my mum until she flat out asked me if I was gay, because my sister is also gay. I wish I had the courage you did.
You can never be sure how people will react to news like this. Your best friend in the world could turn against you, you can't do anything about that. Maybe she is shocked and needs to deal with the news, or maybe she is simply one of those ignorant types? Whichever the case, it will become clearer to you as time passes.
At the moment, I would keep my distance from your friend - make her come to you. Don't push her into accepting you, she must do this for herself. If she doesn't, then it is her loss.
As for your mum, I don't know about that. By what your mum says, she is contradicting herself, and sounds rather hypocritical. I'd ask her to clarify her position - maybe she didn't realise the mistake she made.
I wish you all the best in the future.
