If she is saying things like that, it's probably because she cares, and you are to a point where you need to be on a diet. Obviously you don't want to hear her comment on your weight, as it probably hurts you to think about it. Going on a diet, along with exercise can get you back on the right track to be healthy. The doctor won't judge you, he or she is there to help you. If you don't know your weight, you are just holding the reality back, and it will be harder to face when you get there. Step on a scale at home, and hopefully it won't be as bad when you get to the doctor's office.
Yes, diets are hard to stick to when you are used to eating badly your whole life. Just because others are eating something, doesn't mean you need to. Have some self control, and just don't eat it, eat something that you know is on your diet.
Hope this helped,
Peter
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And it go, eenie meenie mini mo, catch me slippin' never though
Know I keep that full clip, come and get cha super soak
Call me Mr. Cinemax, shoot you like a movie role
Hundred on the highway, let's see how fast the coupe can go