Even at lower MMRs, people prioritize Rets as their main targets. Our bursts are game changers and we very nearly rival healers in our utility to a team (offheals, Hands, etc). Further, they know that you have that delicious Divine Shield that they're going to have to deal with, and the incentive is to make you pop it early and fast to get it out of the way. Nothing's as frustrating as going for the winning blow only to have a Ret bubble and spam Flash of Lights.
So, you're likely still going to be trained and still die pretty quick. Don't have the expectation that some glyph and gem changes will immediately fix that. The only real answer is experience. You'll get better at kiting, LoSing, identifying enemy cooldowns and just... really, getting better.
There's no substitute for honing your skills.