This may be obvious to most shooters but I have not seen it mentioned here yet.
Have you made sure your sight is level????? Before adding a level to it?????
There are lots of sights out there that need to be adjusted or shimmed to be made level.
Just because you buy a new sight and put it on your bow doesn't mean it's level.

The best way I have found is to put the bow in a bow-vice and level the riser perpendicular,then attach your sight (or level to the sight if it doesn't have one already)and see if it reads level,chances are it won't without a little fine tuning of the axis adjustment on the sight.If the sight doesn't have an axis adjustment then shims will need to be used to level it up.
Alot of people will also make their sight level with the bowstring,but remember some single cams will not have a level bowstring even when the riser is level,that is why I like to level the riser instead.