Do you normally shoot with both eyes open? It sounds to me if you were seeing 6 pins instead of 3 that you may have had both eyes open. This isn't uncommon. Often if the light isn't good your second eye will open to try and get a fix on your pins. If you're not use to shooting like that then that may be your issue.
At home when i am practicing i do just fine. Nothing is in the way. I think it may have something to do with the clothes i am wearing. Im not holding everything the same.
Always practice with what you plan to hunt in. I often shoot with a face mask on as well as my camo. It's best to discover these issues before heading a field.