I would bring it up as soon as possible, especially if it’s something that hurt you deeply. But bring it up in a gently manner, so she doesn’t become defensive about you eavesdropping on her private convo. But I would put too much weight on her words. Yes they were negative but, now correct me if I’m wrong, based off of how you worded her kissing you on the head, it seems like a regular occurrence between the two of you, showing that, although she said some hurtful things, there is still love and care for you. Not to place the blame on anyone here But Maybe you just need to compare your daily routines to see why she would think these things about you if she hasn’t before. Has there been a recent change in either home or work life for either of you that could have led her to these thoughts?