Waders full of water will not drag you down since water has neutral buoyancy, but they do give you increased mass or momentum so you will have more difficulty maneuvering in the water.
Wading belts will slow water inflow into the waders. That is a good thing. Float on your back with your knees bent up. That keeps the air below your wading belt up at the top of your knees and it will help you stay on your back. The water below your wading belt will be down at your ankles and down at your butt.
You want to orient yourself feet pointing downstream to protect your head plus it allows you to see where you are going, and to maneuver yourself closer to the bank. When your butt or feet hit the bottom of the stream, work your way into the shore. Do not try to stand until you are close enough to the shore
Regards,
Silver
"Discovery consists of seeing what everybody has seen and thinking what nobody has thought"..........Szent-Gyorgy