So, for some reason Isran and the rest of the Dawngurd are attacking me on sight as soon as I walk into the fort. I just rescued the Moth Priest and did the first crossbow scematics quest for Sorine and hunting down a disguised vampire for Gunmar while I was at it but everyone flips out when I go to turn the quests in. Anyone know what their problem is or how to calm them down? It can't be because I'm a vampire becuase I became a werewolf before starting the DG storyline.

The only possiblity I can think of is I might have goofed a bit on Gunmar's Hide and Seek quest. I was supposed to kill the vampire without anyone knowing but I got a small bounty for assualt (but not murder. Go figure.) The problem with that is that the vampire was hiding out in Dragon Bridge (Solitude territory instead of The Rift) and I payed off my bounty before returning to the fort.

TL,DR: The Dawnguard are attacking me whenever I go to the fort but I'm not a vampire and my bounty is at 0 for all holds. Also, I'm on PS3 so console magic isn't an option. Should I just load an older save and be more careful on Gunmar's quest next time?

Check for vampirism anyway. Your not supposed to be able to catch vampirism while a werewolf, but it's a glitch that happens.

I tried that. I activated a shrine, waited 24 hours to see if I got any of the vampirism warning messages and went outside during the day to make sure.

Well the good thing is you have a previous save, so you can try again. Maybe the game glitched and you need to load said save to continue.