You can change the world difficulty. If you're not there for the boss fights (I'm not, I like the exploration and building), then the lower difficulties will make it easier to focus on other things.

If you do enjoy combat, don't forget to upgrade your armor and weapons. You should also experiment with the different food types to see which combinations suit your style the best.

For boss fights specifically, they all cater to slightly different strategies. I typically fight the first boss (Eikthyr) with a bow, for example, but I usually use a mace for the third boss (Bonemass). It may be that you were dying because your strategy wasn't particularly great for that boss, especially if you went melee - I personally hate Eikthyr in melee.

Final thought: If you're having trouble seeing during the fights, turn off the screen shake setting. My eyes... get dizzy? I like the setting on most times, but I turn it off for boss fights. Particularly fights like Eikthyr, where his light-up, Christmas-y attacks make it hard for me to see all on their own.