I'm Dying More Often as Leona Now ... Need Advice
http://i.imgur.com/BmVkri8.jpg
I main
and she's by far my favorite champion overall (i'm a Support Main) .. she's the first champion I got to Mastery 7 with and the one champion to help me reach Gold (i'm currently at Gold II).
I usually do great, getting from 0 / 2 / 15 or 2 / 4 / 20 ... typically an average score for a tanky support. However as of lately, I find myself dying more and more often now despite I haven't really changed my playstyle. I calculate when it's time to go deep, or when to play defensively ... yet, despite winning games and whatnot, I don't feel tanky enough to survive teamfights anymore. It could be my skills dwindling, but I can't say for certain since the recent patches / buffs made certain champions really strong. Who's to say ... I need you guys to help me out if possible.
See, now my scores consists of 1 / 9 / 13 or 0 / 8 / 19 ... like, my death ratio rose dramatically. Before you guys say anything, I know i'm not perfect. My playstyle might be getting me killed and it's downright flawed now, but it still makes me curious as to how i'm dying way more often, even when I try to play defensively and not go ham.
I usually build 



every game, thornmail being situational since I mostly end up facing a
and so on. Regardless, I am always trying to improve myself but I just can't figure out why I die easily now. If I don't take the hits for my team, we easily crumble but if I go in- even if my team wins the fight, I don't usually survive anymore. Any tips or suggestions on how I can get back to my original score?
Guess it would help if I displayed my runes / masteries too.
is also a factor in why i'm not feeling tanky. I could have 3000+ hp but his 4th auto attacks and his keystone DeathFire Touch obliterates me.