I can't relate to you personally but would like to answer your part of the question where you said you think the depression may be also causing you to lose weight. Yes, what you think and know has a major effect!
Take this scenario for example:
My grandmother went for a checkup in a small town, well known to not have such good doctors, but she grew up there and believed in them.
Listening to them, they told her she had cancer, put her on Kemo and this made her really upset. She got depressed and just knew she wouldn't make it. Well about 6 months go by and they still say she's not getting better.
My mother decided to step in b/c she sees my grandmother fading away! My mother took her to Jackson, MS, a lot larger town and with professional doctors. My grandmother just had scists, not cancer!!!
Where I'm going with this is that yes, just by knowing you have something will bring you down completely. I know you aren't in the same situation but if you could try to keep your head up a little and not think about it 24/7 your depression and some weight should start coming back.
I hope I was able to give you a little insight!

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