depression about weight

To make this short and sweet: I'm the heaviest I've ever been and because I am dieting and trying to lose weight but it isn't working is making me depressed and it's bothering my family and they don't want me to be but I don't know how not to. Or how to ignore the fact that I'm a fat lard that hates looking at myself in the mirror. I can put on a smile but I know that's not me and I'm not going to pretend to be someone I'm not....