The phrase "the blood of the covenant is thicker than the water of the womb" comes to mind. The saying actually means that bonds that you've made by choice are more important than the people that you are bound to by the water of the womb.

Do yourself a favor and find love in your not-blood family. Sounds like they're caught up in their own emotions. (If it's that serious to them, maybe you hit a nerve and exposed a little reality for them hmmmm) They'll either come around or they won't and honestly you should try to only worry about that to a point if you can. Best of luck in the future.