One last resort. Get mad. Really mad. At yourself, fate, casting in general, whatever. Decide you will cast so hard that you will destroy the &%$# rod on the next cast. You will 'make' the leader sizzle on the way past your ear. Stand up straight. Stop the ^%$# rod. Quit babying the fly rod! Hit it! Quit casting like a girl! Step up to it. Either you can cast or you can't; which will it be? Start listening for the backing knot to rip through the guides like a machine gun. A double-haul is never in progress. Either you can or not.