^^^ this!!! I truly thought I was the only one who experienced this. I have pretty much the exact same swimming background and experience. When I first got into the open water on race day, I didn't necessarily panic, but my muscles seized. I couldn't get a rhythm going and every time I breathed, I swallowed water. The waves and chaos then made me panic. I assume the best way to overcome this is to practice swimming in the open water. But I am a little weary of doing that after my last open water swim :/
