One thought to keep in mind is that you don't need to grade yourself or judge yourself based upon what you do in a single day or week. That makes it too much into a game, that for the most part, it's pretty hard to win! Try to look at your health from a distance, and recognize that you are exercising and thinking about making good choices - you are accomplishing a lot.
Regarding food in the house - this can be tough. You just need to insist on your own stuff sometimes - fruits and vegetables, some skim milk - you can do it. I'm impressed by your commitment to this - remember, it takes time...
Negative emotions such as shame only add to the problem.
It's understandable that you would find the situation difficult and demotivating.
Just because a person is a healthy weight doesn't necessarily mean they are healthy. Many thin people are actually fat on the inside. Everybody should strive towards a healthier life/ lifestyle regardless of their weight.
The doctor here recommends incremental changes so that is also a good way to sneak healthier options, etc into your and your families life.
Maybe once your family see how fit and healthy you are they will be more motivated to join you too.
Perhaps trying to change the associations you have with the 'junk' food will help.
There are lots of alternate meals you could be eating. Weight watchers have a free e-newsletter and regularly give healthy meal options. There are lots of healthy recipe books. You may like to invest in one. There are probably also lots of healthy recipes you could access via the net.
Congrats on the weight loss. You should not even consider losing the exercise. You're worth more than that.
Getting your family on board would certainly help with any long-term changes you'll make. Surrounding yourself with other positive people who will support you and your changes is also important. Families can sometimes feel threatened by change.
Don't derail yourself because of other people's views, lack of understanding, support and empathy.
Another good resource if you need it is the emotional eating expert forum and his website shrinkyourself.com.
J