As mentioned, even the week before we had such a happy week together. She said that she'd "gotten good at putting a face on things" which I understand, but I saw her smile and happy at times when there was no need to pretend or for any falseness.
Equally, just two days before, she was very adamant that we we're going to have sex (not that this was a hardship mind), but surely if you'd fallen out of love with someone you wouldn't chose to be physically intimate with that person would you?....
So because she put on a mask and seemed happy to you, you interpret that she was in fact happy inside.
You KNOW how she is feeling.
I think you don't know, again if she is depressed like you how does that really feel?
How do you fix your own depression?
I think you need to stop focusing on how she feels and worry about yourself.
