There was an experiment done with horoscopes that you could re-create if you chose to. You take a group of people and give them all copies of the same horoscope you cut out of a newspaper or whatever. Then you ask them to read it. Afterwards have them raise their hands to see how accurate the horoscope is to their lives. Most, if not all will raise their hand.
The only reason it seems to have some effect on you is that you believe it could be true. It's the power of suggestion. You were in a moment of natural self-doubt and then what she said seeped in and planted itself as an actual idea.
"Astronomy offers an aesthetic indulgence not duplicated in any other field. This is not an academic or hypothetical attraction and should require no apologies, for the beauty to be found in the skies has been universally appreciated for unrecorded centuries."