Playing Sorcerer, at the moment wearing parts of Treasure Hunter set, got all bonuses

skills are all spent on the Sorcerer and light armor, plus some vampire skills. Not using a specific build, rather made my own that I think is the best, using shields and other defensive abilities. But it doesn't matter, because they cut through me before I can dish out any damage

PS: I was somewhat owning others in below 50 PvP with my build, but at 50 even with all purple gear I just die.

Multiple points:
1) When people ask for your skills, they don't mean a blurry tiny screenshot in which you have to guess at icons. Same for your gear, one or two items and making people guess at the rest isn't optimal if you're asking people to help you.
2) Doing well in U50 BGs doesn't really mean much. Although you find some decent people down there leveling up characters, you get a lot of players who have absolutely no idea what they're doing.
3) Why do you hit like a wet noodle? You have very low spell damage, very low max magicka. Furthermore, as far as I can tell you barely have any damage skills on your bar. Past frags, I don't really see much that's there.
4) Why do you die quickly? Well, as previously noted, your crit resistance is low (need to be running more than 2 impen). Your shield is also going to be low, because as previously noted, very low max magicka.
It looks like you're running just the treasure hunter set and everything else is random pieces? That's not going to work out very well I think. Also, if you invest that heavily in crit chance (most of the treasure hunter bonus) and come against an opponent with high crit resist, your crits won't really hit that much harder than a non-crit.
There are multiple foods available for AP; if there's a tri-stat food then that's ok. (Crafted tri-stat would be better).
I'm far from good at mag sorc PvP, but your current setup has a lot of issues.

The trick in pvp are not stats. Try the following monster set + defensive set + regeneration or damage set.

Then organize your skills in the following way one bar is for attack and 1 or 2 defensive skills. The other bar has to have buff or/ and healing skills. That means you throw yourself all the buffs that are the best for you and then your ready to fight. When buff are running out then is time to retreat for a moment, regenerate activate buffs and go in again to the action.

The problem of the feeling of not hitting hard is because usually you are using your skills in the moment the enemy is dope but you will see your damage in the moment their defenses fall down. The same will happen to you. With your buffs actives you will see the enemy is doing nothing to you but then you will start to hitting your enemy hurting them.

Is not about being tanky or glass cannon. Is about to dope yourself. Have good regeneration, don't put all damage skills in all your bars because you need maximum 3 or 4, the rest has to be passive buffs for 20seconds or similar. Have some good defense and that's it.

Try this build:

Infernal guardian or in defect Blood Spawn
Pariah set
Bright-Throat’s Boast

Mundus The astronach
Drink witch's mother potent brew

Skill bar 1
Crystal fragment
Crushing shock
Elemental drain
Hardened ward
Endless fury
Ultimate as your wish

Skill bar 2
Defensive rune
Mutagen
Hardened Ward
Boundless Storm
Power surge
Light's of champions

Items
5 light
2 heavy
All in gold with prismatic defense glyphs and impenetrable.
Jewelry 2 spell power glyphs and 1 Magicka regen

Chest and legs heavy from pariah set
The rest light
Bar 1 infused Destro flame staff increase spell power
Bar 2 infused restoration staff Magicka steal

64 points all to Magicka.
Vampire always in status 4.

Try that and then tell me. Play style is to abuse of your shield, reduce enemy magic resistances, crushing shock, crystal fragments, keep your buffs up, swap weapons heal or retreat, execute them.