I would get yourself a good bow square. Has your knocking point changed? Did your rest drop? Draw your bow back and start there to see if anything has moved. Your knocking point should be fairly level with your rest. You can get an Allens Bow Square, Knocking Pliers and Knock Points from Wal-Mart for around 9-10.00, comes in a kit. It was the best thing I have ever purchased. Now I can change rests, and knocks know im going to be square.