Real quick, given the so-so picture I can see thatthe elbow on your drawing arm is way below the hand and the wrist is bent causing what is an arc in that arm. You're stretched out too far. This is often caused by one or several things. Draw length of the bow too long, which doesn't appear to be the case here. Loop too long on the string and/or the release not being short enough. These are the two I would suggest addressing. You need to get that elbow up so your arm forms a fairly straight line with the arrow. This will ensure that you are pulling straight through the shot and not back and down.

With a picture from behind and above the drawing arm should be in a straight line with the arrow, too.

The only other thing I see is that maybe you have too much hand in the bow. The palm of your hand should not touch the grip area. Way to cure this is to rotate the whole forearm out so the hand is approximately at a 45 degree angle to the grip. Your grip looks loose nd this is good. No wrist strap? You don't grab the bow do you?

There's probably more, like your stance and such, but it can't be seen well with this pic.