Frustrated

I'm frustrated about this: head flat, butt up, kick from hips, head flat, butt up, kick from hips. Today, my buddy and I were swimming, he like a fish and me like a slug. I said I was beginning to get frustrated at not being able to increase my endurance. He said I was still kicking with my knees and not my hip flexors, creating more drag. I have consciously tried to work this out, the flippers help cause they make me feel more flat and relaxed and sort of give me position in my head like I should feel without them. I swim flat with them on a couple of laps. I take em off, swim a length without them, flat and ok, and then...my butt drops and I start kicking from the knees. durnit! I really just needed to vent a little, e-whine I guess, to some guys that I won't have to admit my frustration face to face. But..on the bright side I am better than I was. :confused: I'm really in no hurry, just sort of frustrated at being hung up at this point. Thanks for listening, Mark