That sounds familiar to me too - the lower I feel, the less I can look in the mirror and the less I recognise the person looking back. I think I've always tried to detatch myself from the physical "me" as I was plump as a child (though looking back I was fine) then had a few years in my 20s when I was pretty slim but still felt fat. Now I am more overweight than ever before and find myself repellent but seem incapable of doing anything about it - maybe because I feel I deserve to hate myself.
I hope you are able to talk more about this to your therapist - and if you come up with how to deal with it, please let me know