Are you smithing? Also, I don't have any method of attacking at range, so I find dragons fairly... not challenging or difficult exactly, but they're fun. Although because of smithing my axes are both at 90 damage (dual wielding war axes YEAH) so power attacks from me destroys EVERYTHING. I tend to avoid power attacking because it's so much more fun to just be ATTACK!!!! and take all 10 enemies attacks.
I also fought two dragons at once, one time. It was -hard-.
Blood Dragons aren't much, no. Frost and Elder Dragons are far tougher, though. Also, I have Glass Armor, over 500 defense. @--@