Thank you, everyone for your responses. You've given me a lot to think about.
S, by the way, called me up to offer a small job with her mother... so that was a gesture of good will. I still don't know what i think, yet.
Nadaurz you said something about at different times you could have either been S or me, and that got me thinking about how i'd want to be treated if roles were reversed, and i'd want to be given a second chance if i were sincere. I don't think i'm going to try to fix things with S, but i don't think i'm going to shut the door, either. I think i'll just wait and see what develops.
I don't remember who said it, but you're right... friendships are precious.
msbaby - Have you ever told your friend that you'd like to feel she's there for you too?