Hugs...Definitely tell her you were upset by what she said. Maybe she said the posture thing because she thought it would be a quick way to improve how you look in a picture? Between that and the weight loss thing, it sounds like she's trying to give you advice/tell you what to do rather than just listen. Or talk about where those feelings of being ugly are coming from (and what that means). So I would open by saying that you were upset by what she said last time, that it's not helpful for you to hear suggestions about weight loss/posture/etc. And then maybe try to figure out what you do want to talk about and what would help you?

Also, I forget whether the no-e-mailing for a week thing was your idea or hers. But definitely talk about its effect on you, too. Could you maybe still e-mail her, but just less often?