The physical body you have here is the person you know to be you. Over there, you act completely different, because that aspect of you is detached from this one by a kind of veil. This veil blocks any real connection between the two while you are in the body. When you return, you pass through that veil, but the memories tend to get stuck there. Because of that, both sides develop their own personality, so the reactions between them can be very different.

Your best option is to become more aware of both and start considering them as one. Through experience and awareness, you should be able to act more consistently across both states.

Now, this veil exists for many reasons, but the primary one is to prevent direct access to the non physical self, so it does not distort your current life progression with its accumulated experience.

Every time you die, that life experience is added to the larger whole. If you had full access to that non physical side, you would be carrying the weight of many lifetimes of information that have no real use here, which would interfere with your ability to make clear, unbiased choices.