I honestly don't know what to do.
I've leveled up three classes, and I'm working on my fourth. My guild is doing CT and Extreme Primals.
I really don't think anyone wants to help me play catch up.
Should I just do end game dungeons, and hope I can keep up?
Play at your own pace and don't worry about trying to keep up with others. Use the resources the game has availible like DF, PF, and of course asking in your FC. Do what's fun, though it might help if you focus on one class and do content with that class for awhile so you can do endgame content with everyone else in your FC.