I also use my nose as a second anchor with then cock feather.Switching to that anchor and a couple of other things has just about cured me of target panic.Back to your question.If that happens to me,I'll let down on that shot and try again.If it continues to happen,I'll go to a blank bale and shoot from 2 yards,not aiming,but just checking my form.It is probably a form problem.With that type of anchor,everything has to be lined up just right to get the nose to touch the feather(that's a good thing).It's possible that you draw hand was a little higher or lower on you face.Also,your head position could have been off just a bit.By going to the bale you can check your form without having to worry about aiming.It has and does happen to me.The best thing to do though is not continue to shoot like that.Let down when it happens and check your shot on the bale.Sometimes,our form can be a little off one day and then we can go back the next and it's there again.That's just the nature of archery.