I've taken a look at the losses. mainly cause checking every game is a pain in the butthole. You know, some people do what you want for money...
Anyway. Your last jungle Diana loss is interesting. 350 CS! Great right? Sure! But only 10k damage done to champions. Meaning that you probably taxed lanes and farmed a lot AND never were there when your team was fighting. In comparison, even your Morgana support did 18k (and she was pretty much bottom of the barrel grade) while others did 50k+ with Cait doing 75k.
I'm not sure what you were doing most of the game (I assume farming, cause your cs = Cait's CS), but so little damage done (and 3 kills 1 assist over 60 minutes..) means you were as good to your team as AFKing. Well, maybe aside from lane pushing, but that's not much better than a heralded minion.
In fact, your kill contribution (aka Being In The Right Place At The RIght Time) seems to be quite low. Dunno about CSing (cause a lot of games you seem to be taking support) but it doesn't look good too. I assume your skillshot accuracy is fairly low too (Brand should be doing triple the damage that you have, even as support), maybe try champs that don't require it as much?
Also, drop jungle. It is not your role. 0/0/0 Skarner in 28 minutes is yuck. Just shows that you farm farm farm and don't do the other half of your job which is ganking.