My 10 yr old was drowning and I couldn't find him

Just a nightmare. We all have them.

Not necessarily 'just a nightmare'. All I can say is to pray and ask God to protect your son from any harm that maybe coming his way.

Do you feel your son is in some kind of situation where either he is in over his head or is pulling away from you and you don't feel in a position to help enough?

Its obvious you have a very close attachment to your 10 Year old, your dream I believe is just reinforcing the fact that your child means the world to you and nothing will ever keep the two of you apart unless its something completely out of your control. Its just a dream! You just love your child, that's all! :)