I'd say that your dream is another of the continuing revelations you've been having.
The top of the head is where the crown chakra is and through which higher knowledge funnels from the cosmos. That you saw your spirit floating out of the top of your head seems to indicate that you are spiritually yearning for higher knowledge and willing to meet those higher energies halfway. In other words, you are seeking.
Keep seeking and you shall find.
Nice dream. That is why you felt a welcoming sensation. You are being welcomed to explore--and receive--higher knowledge.