Modern Warfare 2 multiplayer problems.?

I have xbox live and I just tried out Modern Warfare's team death match. It was hard because for some reason I would just teleport all over the place. Not like from one edge of the map to the other, but around my area. I could see myself walking into a doorway and suddenly the doorway moves left of my location! Which means I get hit by the wall, so I try again until I get it. Also while I am reloading, he could just stop his animation and nothing happens! I could also be on a staircase and suddenly I just fall down from it! This also makes it hard to actually kill someone. Such as in a game somebody is right in front of me and I try shooting them, then the targeting reticule just shifts a bit and then I am dead. Is there anything I can do to get rid of this? It isnt fun coming out of a match seeing yourself with only one kill and eight deaths.