Sounds like you handled that well. Good job on not reaching out to comfort her and end the small talk first.
Remember, don't jump for joy at small improvements or jump off a cliff at negative interactions. Just try to put them all on a shelf for observation and keep moving forward. I know it's hard but you're doing great so far.
Here's something from Puppy (I think) to keep in your hip pocket for when she starts talking about breaking your heart or being sad, "Yes, this is hard on both of us." Validating, neutral.
What are your plans for moving day? Are you still going to help out or make yourself scarce?
If you love somebody, set them free. http://tinyurl.com/2empx2g