I was shooting my bow today and on one shot the string got my arm GOOD. I lost the arrow - have absolutely no idea where it went.

I cannot figure out how this happened. I thought I was using the same form (evidetally not!). My initial thought was that the string was stretching, since it is a new bow, but the string didn't get me the rest of the shooting session.

What defeciency in my form would cause this? I certainly don't want to repeat it. I've got a nice welp.