It took me quite a while to get used to short bows. I had to really concentrate on how I held the bow, my anchor, release and concentration. One thing that helped me with short drawing is to draw slowly to my anchor, hold for a second then let it down slowly. Do this 3 or 4 times in a row then rest for a while. Concentrate on every aspect of your draw as you are drawing.
Now if I find myself short drawing I'll come to full draw and hold for a second before releasing. This usually insures you hit your anchor too.