It sounds like you and your therapist really need to discuss why she doesn't want to write the letter, and you should certainly tell her about the anxiety it's caused.
This.
Vw, after keeping weight off for 3 years, my life got a lot more stressful in June of 2004 and I have now gained back 3/4 of the weight I kept off. I suffer from depression, I see a therapist and I’ve gained weight so I can empathize with you on those counts. I feel horrible about how I look right now. BUT certified massage therapists are professionals. They see people of all weights, ages, races and sizes. They’re not going to be paying attention to the weight gain that you are feeling so bad about. You’re just a person in need of therapeutic massage to them. Don’t deny yourself the massage. As someone pointed out, now’s when you most need it. Take Robin up on her offer to make a girls’ day of it.
I’m sorry things have been so rough. Breathe.