To dream that you have a lack of soul or no soul suggests that you are feeling spiritually lost. You need to find yourself and find what will makes you feel whole as a person.
To dream that your soul is leaving your body represents your feelings of self-guilt. You may have compromised your own beliefs and values. Perhaps you are feeling numb and out of touch with those around you. It is time to change some vital part of your waking life in order to feel fully alive and whole again.
To dream that you switch souls with your friend implies that you are not accepting yourself as you are. You drive yourself crazy comparing yourself to others and as a result, you suffer from low self-esteem.
To dream that you marry someone in order save their soul refers to the sacrifices you are making in that situation or relationship. You always play the role of the protector in the relationship and try to shield others from being hurt.