I think you are. Listen, does your family make you do things you hate doing? If not, would it hurt if you try going along with them? What I mean is, do not resist. Stand firmly in your beliefs and values. Speak up if you must. But maybe you should put some effort to make things work with your family. Reach out. Or at least let them reach you. You said that you get irritated if they want you to smile. Did it never occur to you that it wouldn't hurt to smile and actually feel happy? You don't need to make an issue out of it and get yourself stressed. I have the impression that you are resisting your current environment so hard that you're making the situation worse in your head than it actually is in reality. Maybe it's bad, but you don't have to be miserable because of it. And don't work yourself up over the past. You're not there anymore. Embrace what you have now and make the most of it because that's all you really have.
Your family might not be the most ideal one for you, but that's who they are. You can't change them, the same way others can't change you. Try accepting and understanding them the way you want to be accepted and understood. If they say or do something hurtful, be objective- learn but don't take it personally. If they reprimand you for something you're not guilty of, then shrug it off, better yet, laugh it off.
Sorry for the unsolicited advice. And also for being a little pushy. Just thought you might need it.
I really hope you feel better soon. Tell me if you need to talk.