The last part of your post was no help since you don't remember, but the first part in ASL means "You, Me, *blank*, Me"
Having your pointer finger and your thumb being horizontal to one another is the "G hand" because it's the sign for the letter G but I have no idea what it means when it's slid across the chest, so that's why I left it saying *blank* because I don't know, and none of my friends know either. So she either got it wrong, or you're describing it wrong. I'll keep thinking about it though.
Puncia is correct though, signs having to do with the chest have to do with emotion. Did she have any kind of facial expressions that went along with the sign?