The people that moved up, moved up higher in ranks than you. Those that moved down, didn't move down far enough for you to move up.
Example. Frogmonsters are rank 50. A ranked 51 team beats ranked 20 team. Ranked 51 team becomes rank 40. Previously ranked 20 team becomes rank 30.
Just a rough example, I don't know how much moving up and down teams typically do, but I assume that's what happened. Hope that made sense.