Oh Crumpet I'm so sorry that you're going through this!!
You've gotten a lot of advice, and I know you're not responding to your dad's text message so far, but I just wanted to throw this out there: What if you responded by letting them know that you love them all very much but you are disappointed in them for supporting a teaching that you can show them, biblically, is wrong, and that their behavior disgusts you? The reason for such a message would be to let your dad know that shunning you will not ever have the desired effect, which of course is getting you to return to the WT. I'd hate for him to start thinking that this episode might be something that will push you toward returning.
I agree with the others here, you are such a wonderful person and you don't deserve this. Not from anyone, least of all your family. Wanna be sisters??
(((((((((((((((((((Crumpet)))))))))))))))))))))
Love, GGG