I agree Mistlands is hard but honestly it should be. It's the highest tiered zone in the game and it needs to be difficult. Every zone is hard until you start making the armor/food/weapons/tools from that zone which in turn make it easier.

Not sure what gear you have but padded armor lvl2/3 is a must, along with a black metal shield lvl3/4. For weapons it's up to you but lvl3/4 Frostner makes it MUCH easier to survive in the Mistlands. Slow the Seeker or Solider down and then run around to its back and hit it, they are VERY easy when you hit them in the back. The Frostner is honestly a game changer for this zone due to the slowing effect.

Don't go in without Healing and Fire pots. Don't go in unless your eating the best possible food available, Lox Pies, Fish Wraps and Blood Pudding are great examples. You should be eating two HP and one Stamina based foods. Don't run everywhere, take your time and LISTEN. Listening is key in this zone, everything has a very specific sound which gives away what it is and where it is before you even see it.

Set up emergency portals the farther you explore so if you do die it's easier to get back to where you are.

Bring Wisp Torches with you and set a path to follow, this helps establish where you are and where you came from. When you are in a panic they can be very helpful.

Use the Dvergrs as fall back points and mark where they are on the map. They HATE the bugs, use them to help you. Getting chased by a Seeker, run to the nearest Dvergrs camp and let them fight it for you. Eventually you'll need to start killing the Dvergrs but don't worry about that earlier on.