Goon -
Well done. As has been stated, placing does not matter (for now). What you've described, beyond the course, is exactly what most people experience at their first cross race, including me. I think my heart rate on lap two was around 1063, give or take. The good news is there are many, many more races for you to participate in and it does get easier. The panic sensation goes away and after a few races your mind and HR will settle down a bit. It's always hard, but that's why we do it. Cheers or your first go. Wanna try again?
-B