I am a 30ish level assassin type build with Legendary Daedric dagger, sword, and bow. Legendary heavy armor and 40ish one-handed skill level. I get into a melee fight with almost *anything* and die. I walked past a creek and a mudcrab came out of the mud and attacked me. I went nuts with my mighty daedric weapons and had only about 2 centimeters of health bar left before I barely killed it. What the **** is going on? Adept game difficulty. If I can't even kill a mudcrab by level 30 with legendary daedric items, how can I possibly play the game?

Assassin wearing Heavy Armor and only 40 or so points into One Handers - at Level 30?

That might have something to do with why your having issues.

What armor and weapon perks do you have?

It does sound like your skills are seriously unbalanced.

What is your heavy armor skill at?

Ooooh. Did you power level Smithing by any chance?

I've run into that issue before - grinding out Smithing and levels...then discovering my combat skills are woefully inadequate for the difficulty spike.

I'd say something definitely isn't right.

A daedric dagger, smithed to legendary, should kill a mudcrab in one hit. My adventurer (who has no perked weapon skills), can kill one in about 3 hits with a steel dagger.

I'm thinking the same, especially with the op having Legendary tempered stuff.

^^^ this is probably the problem. Three choices, deal with it til you can get 1h skill up by fighting and dying or Train as much as possible, then fight, then train... or scrap the character and learn a lesson about grinding smithing.

Have you changed your INIs? If so you might not actually be playing on adept.

How high is difficulty level? Sometimes people change it (and forget), which can make the game considerably more difficult.