As others have said you can run immovable pots, I wouldn't recommend stamina abilities that grant said immunity on a magic build as stamina is precious.

I'll assess the Sorcerer's abilities, not assuming any sort of ignorance on your part, but to help you consider the options holistically in terms of the class. All of which are simply options.

Your counter to CC as a sorc is to CC really;
[Crystal Fragments]: time it right, knock them down can in turn be in your favor depending on whatever other abilities you are running.
[Restraining Prison]: Can help slow down combat, force players to burn stamina, not the best option as some things can be immune and it costs a bit of magic.
[Defensive Rune]: Works very well against ganking which is usually initiated by a CC attack.
[Daedric Mines]: As others have said, maneuver around these, they last long, deal great damage, heals you (refer to the Blood Magic passive), and immobilizes enemies.
[Negate Magic]: Removes enemies' support buffs, silences in pvp which can really turn the tables when concatenated with a CC against clusters of players, not so useful in pve as a CC because it stuns and there are so many other sources...

You can use other entities to take CC, damage, and agro from you;
(All sorc pets): Can ensure holding agro of at least one NPC each, in pvp players can struggle with targeting, wasting spells, I don't recommend them on console because of the countless times I use the pet command function on PC, but they sure keep players moving (disregard idiotic statements about them being "squishy", saying that actually mean "I don't know how to use pets", which is fine, however, if they did then I along with any others who rely on them wouldn't be able to take on groups solo).
[Volatile Familiar]: DoT AoE followed by a stun, keeps players moving (or not at all when stunned).

Counter CC by mitigation and mobility;
[Conjured Ward](Morphs): When you get CCed or get hit by something, this will buy you time to react and resolve with little if any damages at all.
[Bound Armor]: Can improve your barrier('s/s') strength (there are other good methods of stacking max magic, but in terms of sorcerer abilities... this is the one), the ~2% resistance can be neglected as it is only applied when the barrier is down.
[Lightning Form](Morphs): Grand movement and ~7.5% resistance, again, resistance only applies when ward is down.
[Bolt Escape](Morphs): Stun, teleport and stun ahead, or create a ball of light to absorb the spell projectiles.

Remember to keep pressure...
This is probably the hardest part about sorcerers in pvp, AoE only diverts player movement, the sorcerer abilities revolve around; AoE DoT, proc, and timed/delayed damage. If you are not applying pressure then you are most likely going to spam defence into a loophole and, inevitably, get CCed till you start pressuring, escape the situation, or die. I would look at your sources of damage with your current setup (if you stick with it) and evaluate on how you can force others to go defence so you can ease on defencive play.

I personally run a willpower sword and shield, so weaving heavy attacks sustain my stamina and allows me to break free and do some interrupting without worrying about my small stamina pool, the 2x willpower with magic enchant gives me ~4K max magic which helps counter not using a staff (yet makes my barrier stronger).