Whatever you do...do not talk to W at all. Let her approach you and bring up whatever topics she chooses to do.
The principal talking to you about these issues suggests that there's an office gossip going around the teacher's lounge and it stinks that he brought these up to you. One, it is nice that they're concerned about you and seem to care about you. I question why your W spoke to the principal as it seems overreaching on her part. There's a part of me that wonders if W is planting some seeds to portray you in a negative light. Again, that's assuming the worst from W.
Back in my previous post, it is best to lay low and do some damage control by posting positive, upbeat, and innocuous topics on your FB page. Then do what my friend Bets (Underdog) does...put on your best Bob Barker face...and fake it until you make it. You've seen the tv show The Price Is Right with Bob Barker as the host, right? You've seen how he smiles perpetually and spreads the good cheer around during the show that generates good feelings and goodwill among contestants/audience members.
Can you do that at your workplace? I think so too! Keep up with the good stuff and ignore the naysayers.