I know how you feel.
My own mother mocks me...I think she is only joking, but she doesn't know how much it hurts.
Anyway, I think your dad should leave you alone. You have enough to deal with as it is without the stress of your dad harrassing you.
As for your Brother...brothers are jerks. I don't have one, but I have a cousin who is like a brother to me and he is a jerk at times too. I'm sure that when he gets older (if he is young now) he will become mature.
Just to say...I don't hate you. I think no one deserves to be hated for their differences, unless they are intentionally being nasty, which I doubt you would be doing.
Try not to let people get to you...they are the idiots, not you.
I hope you feel better soon.
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I = Vegan!
Animals = Friends.