You pretty much have to get your butt handed to you until you reach enough points to buy Equanimity, which allows you to cast uninterrupted for 10 sec. Spec'ing more into that gives you more time and shorter cool down.
Another action to buy is the one that removes all negative effects. Forgot the name of it but works just like the PvP trinket in WoW.
All in all, I actually like PvP. It just takes a bit of time to acquire the spells that will make you viable.