OK I been there and bought the teashirt so some thoughts for you.
I assume your guild is casual if you are only doing PR and wiping on the last mob.
If the guild is making progress even if its slow and you like the people then stick with it. We all get ups and downs and the bitching and moaning is generally worse when your having a tough time with a mob it takes time and effort to learn mobs and its always the Tanks/ Off Tanks fault.
What are your options
1: Go hard core and raid 7 nights a week, if your good enough and if you have the time and if you can get a slot.
2: Change guilds find another casaul guild that has a raid slot for a Paladin ( most have more paladins than they need) find your self with the same problems and frustrations with different people.
3: Leave your guild becuase your pissed off and wander untagged looking for a new home.
4: Take a break from game without deguilding.
5: Take a deep breath count to 10 and stick with it.
