This is exactly how I felt before my last climb to 2100. Got to 1700 went back down to 1400 then sat around 1600 for a little while then eventually got two or three good streaks and got the gun. It feels like the game is designed to make you almost want to quit and then give you matches where you have a much greater chance of winning. But stick with it. You know whether or not you are good enough to get it and if you believe you are then you will.