I haven't shot my bow in about 4 to 6 months. Now my sighting is off. I have checked the weight and it still is at the same poundage and my sights are still at the position where I have left them (a mark was placed to ensure that it was at the right place what else could be the problem?

Your Form

If it is not form could be some string stretch as well....

Then his poundage would be out of whack wouldn't it?.

if the string stretched, your poundage is set on the limb bolts, not the string length.

Are you Right Handed? Right Eye Dominant? and are you shooting to the left?

If so, its your form. If you are a lefty and hitting right it is your form.
There are other things that could be form as well but, you usually are not able to hold and follow-thru when you first start shooting again and "throw" you arm outward, thus hitting left for Rt hander and right if a lefty.

Is this what's happening?

I'm not pulling to the right or left. But I have use the next lower pin to hit dead on instead of the pin that it was set at.

sounds like you're anchoring differently than when u shot before

String streach would be my guess!! Walt