If I'm looking at the right product, you had something like 9.25 gallons or 78 lbs of water strapped to the top of your rack. That's way too much. Most racks aren't even rated to carry that much weight. Even if the rack can handle the weight, as you discovered it's going to ruin your balance and stability.

If you're going to carry that kind of weight and volume with any regularity, a trailer or cargo bike is the way to go. Even if you can make it work on a regular rack by unpacking all the individual bottles, it's not going to be much fun.