Fear of rocks under water
I have a fear of rocks (and sometimes other things like logs or pipes, but it's mostly rocks) that are underwater. Not small rocks, but big, boulder-like rocks. Why is this? I can't go swimming in a lake or ocean where I know there are rocks, or where I can;t see the bottom, because I'll be afraid my foot will touch a rock. Is anyone else afraid of rocks that are underwater?
Even when I go kayaking, I hate looking over the edge of the kayak and seeing boulders that are underwater. It freaks me out to the point of having a panic attack. Is it normal?