You hold your head high and you brush off what they say. You ignore it. If someone says things that are that hurtful to you, there is something wrong with them. Not you. I would love to be a size 4 again! Try and surround yourself with positive and not the negatives. You look at all you've accomplished, overcome and are still going.
I've never quite understood family bringing other members down. Mine does the same thing. Telling me I can't do this, I'm that, making fun of me, etc. Yet I have others who look at those same family members and laugh at them. They are supposed to help and encourage.
Just try and smile. No one is perfect but no one has the right to try and tear you down. I am sure you are a beautiful person inside and out. You don't need them to tell you what you already know