About three weeks ago bow started shooting left. I moved my sights to fix it. After I would shoot a couple of days I would start shooting to the right. I moved my sights back to original place and would shoot dead on. After a couple of more days it would go back to the left again. Been shooting for 4 years and have not had a problem like this. Is there something in particular I can check on my bow for this problem or could it be just poor form? By the way I paper tuned to check that and it was still tuned shooting bullet holes. Would appreciate any suggestions.