Black Ops gripes and what not?

I have done nothing but complain about this game and yell at it for the last week lol. I was on such a good streak and then this week has went to ****. It seems that one week I cant kill anything, then the next week one shot kills every one...not its back to unloading a whole clip into some one and not killing them. is there some kinda glitch on this game, or what is the freakin problem. I have a 1.6 K/D ratio so I like to think Im not terrible but it just gets old how inconsistent it is. any one else having this problem or anything like that...