Pitching Mechanics Help?

I have a high leg kick and about a 3/4 delivery with an occasional over the top or drop down and I'm starting to feel some mechanical problems. About 3 weeks ago I felt great with my pitching and my pitches were coming along well. But as of the last week or so I feel as if I've lost it. My breaking pitches are flat and have almost nothing on them, as is the same with my fastball, all I'm all over the place and throwing meat. In my delivery I don't feel any momentum toward the plate and feel sometimes as if my arm is dragging. I've tried speeding up, slowing down, and different arm angels in my delivery but it seems nothing has prevailed. I don't know whats wrong or what to do, any advice would be great.