Being with yourself in the moment is a real interaction between all the possible versions of yourself and the version of yourself that exists right now.
Just to be clear, you can be with yourself and with your thoughts at the same time.
The difference is whether the relationship to self is being actualized.
Is your current self being seen in the context of other relationships, with your environment, with others, with real or imagined versions of yourself?
When you have an actualized relationship to self, it means that you are aware of the context of your experience.
It is the process of finding yourself where you really are.
And being connected enough to what is external to you, both in space and time, that you are integrated into the larger web of reality and life.
Being with your thoughts is a self-contained interaction between the current version of yourself and that version's current musings.
Every thought is an abstraction of reality, and it is confined to your mind.
In this way, being lost in thought is a single dimensional relationship to your experience that involves only one real being.
It does not involve any real interchange.
Of ideas, of feelings, of energy, of recognition.
The only interaction is between one version of “you” and the thoughts that it is lost in.
It is an inherently isolating experience, not just from others, but also from your environment and your true self. Your big self.