Did you ever see any enemy players? If so, it's probable that the times you couldn't see enemies were when you were being attacked by stealthed players (especially if all the attacks hitting you were ranged).

Nightblades are annoying to all classes, I'm a Nightblade and I find enemy Nightblades infuriating. Either you can't see where the attacker is, or they are so fast you don't have time to react before you're dead as they appear from nowhere.
I'm very suprised you didn't see anyone unless you were at a empty fort that had been recently captured and everyone had left, or a fort that was empty and about to be captured. They like to hang around a fort at these times to stealth attack small groups, and especially lone players. If you are A lower level you are also seen as easy prey.
Next time you join look on your map for a broken fort, or crossed sword symbol with your alliance colour as one of the sword. Teleport to the nearest fort and head for it. The same might happen on the way as you get ganked by Nightblades. When you get to one of these places if you still don't see anyone you've got a problem, if you see a full on war you know it was those bloody Nightblades everyone moans about.