Look the the ground connection, I.e. your form. I would make sure to check over everything on the bow quiver. Make sure all the connection points are tight, the contact surfaces with the bow are not worn etc... If nothing has changed on the quiver, then the problems are either with the bow or you. Most likely it is form.
Have you changed your arrow weight significantly? Loading up 4 to 6 arrows the weigh an extra 100 to 200 grains each can change how the bow sits in the hand and how the bow shoots based on it.