I have (and probably most thieves) run into the same issue you are having. Unfortunately thieves must rely on stealth and mobility in order to maintain any type of survivability, which is why I enjoy playing as one. This however, does not mean you have
to go glass cannon and just "learn how to dodge". I personally do not enjoy the glass cannon builds and would rather have more drawn out fights than relying on bursting someone down in the first few attacks. This is not to bash glass cannons, I ran with one for a while and had some success, ultimately I was not very good at it and it was not fitting my playstyle for WvW (spvp i prefer a more glass cannony build, but I rarely play any other pvp than WvW).
As I said above, you do need to learn to rely on mobility and stealth in order to survive. Pouring some extra stats and traits in more defensive lines will still leave you rather squishy, but you will gain some pretty awesome tools for avoiding
damage. That being said, I think you should ask yourself if you want to focus more on skills that will enhance your abilty to stay in stealth, or focus more on mobility.
I have tried out a build using 30 points in shadow arts, and have taken the shadow rejuvination trait. It is a very viable path and I had a lot of fun going in and out of combat and practically healing myself all the way up in stealth. The only issue I had with this build was the lack of stun breakers and condition removals. I found to make a stealth build worth it I was taking black powder, shadow refuge, and (of course) signet of shadows. Although the build was fun, I often had trouble when I was happened to get locked down with stuns and conditions. This was usually the case when I was outnumbered, but it really came down to my lack of skill to keep an eye on reveal c/d and blowing my black powder or shadow refuge too early. Also, I often run with a small group of friends so I found constantly being in stealth not as necessary as it would be in solo circumstances.
If you want to go this route I would suggest speccing 10/30/30/0/0. There are obviously other variations, many of which people will probably argue are better. But I found 30 points in shadow really made the stealth worth it. I usually pick up Furious Retaliation, Critical Haste, and Executioner in the critcal strikes line. I personally like Master of Deception, Infusion of Shadow, and Shadow's Rejuvination in the shadow arts line, but there are many other good traits that you should play around with. You will see many people suggest a build with some variation of 25/30/x/x/x. The minor trait at 25 points in deadly arts is very good, but I found the other traits to be a bit lackluster and was willing to give up the dps to invest more in some survivability. So whatever you choose I would suggest putting atleast 10 points in DA and grabbing the mug trait and the extra power you need for good dps.
However, this is the build I use.
I am still changing some traits around and still contemplating a full 30 points in acrobatics, but I find myself enjoying this build the most. Once you spec into Feline Grace on the Acrobats line, you will find yourself dodge starved with any other set up. This basically gives you a third dodge. That added with might and swiftness and the +10% damage when endurance isnt full is absolutely incredible. To make this build even better, get your hands on a Bowl of Orrian Truffle and Meat Stew. 1 more stack of might on dodge and 40% more endurance regen synergizes very well with this build. One of the reasons I spec'd out of the shadow arts line was because of was seriously missing the Shadowstep utility. Double stun break and 3 cond removal is almost essential in WvW and I now can't live without it.
Hopefully this rambling post with way more info than you want helps you in some way. Sorry for the length, I got a bit bored and carried away. The main thing is to get some more money and try out these builds and more importantly your own variations. You will find you can definitely add in some incredibly survivability without taking a serious dip in dps.
Also, I found this thread to be very usefull