I've never gone through anything like that, so it's much easier to talk about it than it is to actually go through it, but I suggest telling your mom and your brother that they aren't normal either, and just because you differ from them in one way, doesn't mean it's wrong, because they're also different from most people in some way. Especially if you/they are religious (Christian), I would tell them that God says all sin is equal, and they shouldn't treat you being gay like something terrible, just because they don't understand it. I knlw they're your family, but anyone willing to hurt their child just because they're different isn't someone you should let affect you deeply. Parents should have unconditional love for their children, and if they don't, then there is a problem with them, not you.