Baby Ball Python not eating... PleAZ Help!!!!?

I got him 3 weeks ago. He was a hatchling when i bought him. He cannot be more than 5-6 weeks old, and no thicker than 1 1/2 inches thick at thickest. 18 inches long. He hasn't eaten yet for me. Ive tried live, and frozen. Ive tried rat hoppers, mouse fuzzies, and small mice.ive tried to feedt in a bin, a box, and in the vivarium! Any other ideas. He also has had jerky head movements