Hunter has some of the best defensives in the game currently, after we got the rework. But it IS something that require a bit of figuring out.
So it’s not unusual to see people struggle learning how to survive.
Here are a few tips:
1. SV Hunter is NOT a melee spec!
Yes you have a sword instead of a bow, but 90% of you rotation is ranged.
Don’t see SV Hunter as a melee spec. This is the biggest mistake people make, and then they die constantly.
You only have Butchery and Mongoose Bite/Raptor Strike as melee attacks… and even then, you should make sure to use Aspect of the Eagle as much as possible, to use Raptor Strike from a distance. 
DON’T fight near the enemy. If you HAVE to move in to use Butchery for AoE, IMMEDIATELY get out again to get distance.
2. Use utility
Hunter is a class that REQUIRE you seeing your traps as part of your “defensive toolkit”. So try to alternate between the traps one by one, and if done so correctly, the first trap should just about be off CD again.
So use freezing trap, tar trap, scattershot, explosive trap, and your 2 stuns in rotation.
We have LOT’S of CC.
3. Don’t use SotF too late.
Survival of the Fittest, is an incredible defensive, and you should make sure to use it when you expect damage… and not after you already reached 40% health left… same goes for Aspect of the Turtle, which btw you should also focus on using traps right before it’s effect ends.
4. Use pet ability BEFORE using Exhilaration.
By having a Tenacity pet out, you gain 5% more maximum health.
On top of that, your pet ability is Fortitude of the Bear, which not only heal you for 20% health, but also increased your maximum health by that much during its duration.
Why is that important?
Your main healing spell Exhilaration, heals based on “health percentage”, so by increasing your health pool using a Tenacity pet, both 5% passively and 20% using Fortitude of the Bear, you heal for MUCH more if you press Exhilaration after. 
Additionally you can use a trinket that increases your maximum health (for example the PvP trinket), before pressing the above mentioned, to heal EVEN MORE with Exhilaration.
You basically have a “mini Paladin Lay On Hands”… 
So use pet abilities and trinkets to squeeze out as much healing as possible. 
There are more tips, but that’s all I have time for for now hehe. Am on my work break writing this.