This is normal, and that protective mama/papa bear mode showing itself in full force.
Showing your child that balance is your best bet at living a mentally healthy life, will help your child have those same behaviors. Talk openly about wanting to take away his sadness and worry, but that it’s impossible for you to do that. Remind him that he is the only one who is in control of his thoughts, behaviors and feelings. Let him know what you do to be in control of your own happiness (spend quality time with family, go for a walk in the sunshine, etc) and ask him what he might do to be in control of his happiness too.
Stay brave and keep role modeling that consistency and balance out loud. The more they see you doing it, the more they will do it too.
