I've had what has been diagnosed as "Atypical Depression," over and over again. It was nothing like what you are describing. It was extremely severe and lasted several months to years.

I do understand BirdDancer's experience/description as being a part of transitioning or stabilizing within the experience of BP.. I think it's likely we all experience this.

The description you have given, Blue, sounds much more like a personality type of an issue to me. I believe I have read rapid mood changes based upon these types of external events are more likely BPD. However, I am not a pdoc!

Is It Bipolar Disorder or Borderline Personality Disorder? | Psychology Today