This is a rite of passage for many ducks and their caregivers.
Breath...Have a cup of hot drink. It's not your fault, it is their survival instincts kicking in.
I would stop putting them in the pool for at least a couple of days. Stay as low as you can. If you are able, squat down as much as possible. Sit next to them. Announce your arrival with some sweet soft sounds. And pull out the treats. Avoid cornering them. Lure them with treats to where you want them to go. Keep talking, talking, talking to them - sweetly.
Time with them, seated or even lying down, and treats will help. It may take several weeks for them to get through this, and they do.
My runners are friendly and sweet, but went through this from about age three weeks till nine weeks.