ok have you ever noticed how soft the ground gets after a rain? and he dt said it had snowed as well. maybe u missed the deer maybe you didnt. but think about this. you had already spooked the deer right? maybe tis buck jumped the string (hence you thinking he hunched up, when he simply dropped down) and your arrow came close enough, or maybe even grazed him to make him jump( hence mule kick). that would explain a complete lack of sign. if you had hit the deer there would at least be hair on the ground. and could explain your lost arrow as in soft wet ground arrows can really bury deep.

anyways thats just my take on it