How do you choose between your sanity and your family? How can you make the decision to walk away from your own family, even if you know it's best for you?

I can't answer this question - You are the only one who knows that. However, i think you shoudl weigh out the positive and negatives of the situation. Don't over think it too much. You will make excuses for the choice that you don't feel is right.

Counseling is an option, most of the time it is an effective way of helping everyone. I would consider taking a few counseling sessions together before deciding anything to irrational.

First question: Has it come to the point of choosing one or the other? (Why or why not?) Second question: If the answer to the previous question is yes, are you prepared to walk away if your farewell/announcement conversation with them doesn't go as expected (e.g. they get angry or beg you to stay)? I trust that you're going to walk away in the best way possible--something only you can identify--without creating bitterness when you leave for your break, but even when you do your part, there is no guarantee it will be a clean farewell. It's best you also prepare for this scenario, and not just your goodbye speech, because if you tell them such a thing it will only create further tension in your relationship even if you decide to stay after all. How right is the time?