Nocturne Help?

So recently I've been playing Nocturne jg, doing decent with him (as in I'm not feeding and I'm picking up kills nicely, ganking at appropriate times, etc). But at the same time, I keep losing games even though I am carrying (5 games in a row lost) I realize that this may be my fault, and I say so because I don't feel confident that I am doing so great in teamfights, even though I am fed. Any tips, help, anything?