A counsellor shouldn't be telling you what she thinks. She should be asking you what you think and reflecting it back to you:
Her: Do you think he was being shallow?
You: Yes, I suppose I have been worrying about that
Her: So you are worrying about him being shallow?
You: Yes I am!
The idea of counselling is for the counsellor to shine a light on your feelings for you, so that you can then work out whether you are in a good place. You have done that here: you are worrying about your weight. You believe that the culture you live in (do you read celebrity magazines?) mean that to be older and fatter is less attractive. You are now worrying that your boyfriend feels the same . . . .It's called projecting. You are projecting your fears onto him, so that you can blame him for them, rather than consider what you feel.
First, actions speak louder than words - does he love you/look after you/show he cares/talk to you/make you happy? Has his attitude to you changed since you have put on weight (or are you just worried that it might)?
Second - you have been through a difficult time, and have been comfort eating. Lots of us do that. It's not a crime (despite what a lot of our press suggest!) If you are getting some exercise, and eating sensibly most of the time and (most importantly) getting help for your problems so that you don't need to comfort eat - then you are doing well.
Third, if your culture is telling you that you have to be young and thin to be beautiful then think carefully if this is the culture that you want to be part of. We are a multicultural society - lots of groups of people with varying beliefs. Belonging to a group, reading their literature, making friends within that subculture - all of these activities reinforce those beliefs. I was ill once (in the days before the internet/24 hour TV) and a friend lent me a huge pile of celebrity magazines. Each day I could feel my self esteem slip, looking at the images everyday of young, supposedly successful/happy, thin, beautiful people. As soon as I was out of bed, I returned them all, pronto. Beautiful people, for me, are the people who do lovely things for other people, who are generous, who make me laugh, and who (usually) share food and wine very freely. But that is part of the culture to which I now belong. Doesn't that sound like a healthy place to be? Use counselling to choose where you want to be, and find out whether your boyfriend would like to be there too.
HTH