I feel like I'm missing something. I just walked into Dayspring Canyon to start the Dawnguard quests, and I'm being attacked by everyone on sight. I don't think that's supposed to happen. Anyone have ideas why?

I went back to a previous save and it's ok now. The only thing I can think of is, just outside of Dayspring, I got attacked by wolves and accidentally hit a dude who apparently was trying to help me. Then they attacked so I had to kill them. Maybe they were Dawnguard or something, I dunno.