Hey pilot, I'm a pro at mind reading so I'll give it a try. Sounds to me like your W is having mood swings. But yeah I wouldn't take it too personally. Maybe the kids are getting on her nerves, maybe she had an argument with a friend or family member. Or maybe she is annoyed with you. Who knows! But no matter why, just let her have her moody moment and as other people said just be your positive self.
I know when I get in a mood the best thing for others to do is ignore it. Because it passes on its own like a dark cloud. You are mad about something or irritated and then it passes. If there is a reason and she wants to tell you, she will.
I don't think there is a reason to suspect OM, but that could be the case. Maybe that explains her mood swing. But you don't really know so don't assume. But I agree that the gut instinct is often right, alerting you to something amiss. Not necessarily telling you the correct details though. Could be that there is OM bugging her for some reason, positive or negative to your situation. But who knows.
You are doing great with your PMA, GAL etc. Keep on going! Slap a smile on your face like I did today. It was hard but it paid off.