Wow, that is a powerful meditation, if I do say so myself, ha ha. The long and the short of what you ask is yes it could be the soul of that same child waiting for his opportunity to return to physical life. It also could be a different soul whose time has come for their incarnation into physical life. Sorry I can not be any more direct with my answer. The timing of the meditation and then the realization of your pregnancy is not a coincidence.
That meditation and the visitation from your son was your heads-up of what was to come. It could have come thru a dream or in many other ways, your son chose that meditation to let you know he was okay. He never made it here in the physical sense, but years later decided to let you know he was okay, that is a powerful statement of love and a perfect example of the connection we share with our loved ones, regardless if there ever was a physical connection. People often wonder why a grandparent they never knew or had very little contact with in life, would show up in a reading and dominate the course of conversation the reading takes. This is a prime example of how the bonds of love continue on.
I wish you a wonderful pregnancy and birth and know that your child is meant to be here. Thanks for your question.