This is not a "git gud" post... well, it kinda is, but I'm going to explain why you're dying and how to stop doing it, so it's not one of those "git gud" posts.

• Eat food. Your health is capped at 25 HP unless you eat something.
  You can eat up to 3 different somethings at a time, which will dramatically increase your health and stamina, leading to better combat proficiency and longer sprinting ability. There are two berry bushes and two little red mushrooms on the outside face of the stone circle you spawn in; pick them up and eat one of each.
  
  
• Speaking of sprinting, stop it. Sprinting everywhere just means you're out of stamina when you run up to the mobs and... fail to punch them in the face, because attacking requires stamina, too. This game is much slower-paced than the ones you're used to playing, and sound plays an important role in the aggro mechanics, as well; running is louder than walking, which is louder than sneaking... which means the enemies can detect you from farther away.
  
  
• Learn to block. That's right-click on the PC, and I'm sure the button is labeled on XBox. You don't need a shield to block, and none of the mobs in the meadows should be able to actually hurt you while you're blocking... if you've eaten something.
  
  Practice by picking a nice open area, 15-20 feet should do it. Aggro a greyling, but don't try to kill it (yet). Time your block so you block while they're swinging; that's after they start swinging, but before they connect. As long as you're blocking before they hit you, you won't take more than one point of damage per hit... and if you've eaten something, then you will regen that back before they swing again.
  
  If you time your block correctly, you will be rewarded with a "kaching!" sound, and the enemy will be briefly stunned... which allows you to get in a few good hits, the first of which will probably be a crit. This is called "parrying", and is probably the second-most important skill to develop (the most important skill is called "dodge-rolling", but that's much more difficult to learn - work on blocking and parrying first).

There is ever so much more to this game, but the information I have provided so far should be enough to get you up and running.

Good luck, and have fun!