2-hit you?! How did that happen?

When I solo'ed the first boss, it was able to get me down about 85% of my total health, and I was wearing troll hide armour.

1. Are you wearing any armour? Make sure to wear at least all troll and leather armour.
2. Are you eating any food? Make sure to eat 3 different types of food.
3. Use a bow and flint or fire arrows.