how do you know when you've been overshooting?

Consistency is not there..........For me, if I shoot everyday, my consistency suffers. I have found that about 2-3 days per week is plenty for me and keeps me in shape.

When your arms start getting tired, your pins start swaying all over the targer, your groups start to open up, it gets increasingly harder to draw the bow

When my wife says she is pregnant.

I'll second that.