I hope things get better with your family. All I can say is that my family has a lot of "politics/tensions" that have gone on and on for what seems like forever and I totally understand how these sort of things can lead to emotional eating/making poor nutrition choices. It'll take some time and practice, but, you can be successful in curbing emotional eating. So, don't give up and do stick with it. Remember that you're doing this for yourself so that you can be healthy.
Today, try this... Don't say, 'I'm trying to get back on track." Tell yourself, I AM back on track. Be determined. Do it for YOU!