Getting killed in a dungeon can be hard. I know, I've been there before. Here are some tips to get your stuff back.

1. Eat up on the best buff food you have. If you go into the Black Forest, you should eat at least deer, pork and honey. (I assume you do not have the cauldron yet.) That will give you at least some protection when doing the next step.
2. Naked corpse runs are a thing. Do not have ANYTHING in your inventory, so you can pick yourself up with a press of a button (E key) and run away. I know this is hard in a dungeon, but you can do it! If you press the V key you can toggle between auto pickup or no pickup, so you don't actually pick up stuff during the run you don't want.

The point is to be always(!) well fed. If your health is high, you can take a lot more hits before you die, and with the corpse run buff (stamina drain is very low once you have picked yourself up) you can run away from anything threatening.

Run away in the direction of your home. Have a home not too far away when braving dangerous new grounds. If need be, renovate an old hut to act as a forward operation base, so you can be save inside and can repair yourself. Have at least a fireplace, a workbench and a bed there. Chests are good to have as well.

Good Luck!

Edit: A level 3 wooden shield will protect you from anything in the Black Forest, except, well, Trolls.