I started a couple of months before you and my biggest problem in any PvP game has definitely been inconcistency. Inconcistency affects everyone and I don't feel like it's that big of an issue. I've lately started off my weekends with 2.5-3.0KDs and have it falling to about 2.0-2.3 towards the end of the weekend. When I play too little I feel my game suffers, when I play too much I start being sloppy and/or tired. There's a soft spot after I've gotten warmed up until I just get sick of playing. There's no easy way to solve it, but my best suggestion is to make sure you take breaks. I tend to get pretty tilted the more I play also, and if my attitude is bad then it will definitely affect my play. I unfortunately don't really take any breaks, I'm at work a lot during the weekend so when I have some extra time I usually use it to play Destiny. The best advice I can give you though is to stop caring about the dips in skill, just make sure you keep improving overall and after a while your dips in skill will be equivalent to your current peaks.