This is only a guess but I am thinking you are having problems with your pin floating all over the target. So far this is normal. The normal but disasterous response is to hit the release or let go when the pin is going by center. The arrow goes well off course and you kick yourself. Am I close?
Typically, an archer who is using a release, has become comfortable with punching the trigger at the exact moment that their pin crosses the target. And, usually up until that point, they are doing pretty well at hitting what they are aiming at.
But then... they notice a slight flinch. Still... the majority of their arrows are on target... but every now and then... they have a few "fliers" due to this little annoying "flinch". If not corrected... it continues to get worse, until their confidence is shot, and they are not sure if they can hit the target with their next arrow.
First off... Shoot some "Blind Bail." Get within 5 feet from your target, and shoot with your eyes closed. Use proper form, and slowly squeeze your release. Your release should be UNEXPECTED. Do this and allow your body to feel what a "Proper Release" feels like. In this manner, you are developing "Muscle Memory". Do this with about 10 arrows before you start shooting... and then about 10 arrows after you finish shooting. (Again... this is done with your eyes closed.)
As Bob mentioned, allow your pin to "float" and don't get too concerned with the "Perfect Sight Picture". Over time, you will become more steady... but for now... let the pin float. At this time... don't be to concerned about where your arrow goes, but instead, be concerned that you are triggering your release in such a manner that the release is "unexpected" or a "surprise."
When you aim, you should pick a spot, and absolutely "glue" your eyes to THAT spot. DO NOT take your eyes off of that spot! Allow your pin to float... and do not take your eyes off of that spot!!! Slowly initiate your release in such a manner that the release goes off by surprise. When you release... DO NOT look for your arrow! Continue to stare at the same spot.

If your pin was not on the exact spot you wanted... Don't sweat it! What you want to do, is to be able to tell exactly where you pin was located at the exact moment of release. This is done by gluing your eyes on the target.
If you can say... "My pin was low left"... and that is exactly where your arrow went... you are in good shape! Again, you will become more steady as time goes by. But... if your arrow goes someplace else than where your pin was during release... it will be a problem in your form.
The key to this whole thing boils down to (3) three things...
1) Proper form.
2) Allow your pin to float.
3) Your release should be a surprise.

If you can nail these three things down... you will find that you no longer flinch!
Good luck & please keep us posted as to your progress!
Allen