If she reaches out, the more succinct your reply, the better. "I'm not coming Sunday. I decided 'just friends' doesn't work for me." This communicates Sunday is a no-go, just friends is a no go, and you get this is a change. Avoid watering down your message with justifications or soothing words. Avoid future predictions that set you up for failure. LBS often talky-talky too much when less is more.
