As others have said, the swamp is a significant step up in difficulty and probably requires an adjustment in how you approach it.

Find nearby Black Forest or Meadows and build a small base there, then head into the swamp on foot each time. This should also have access to the water so you can easily transport ore somewhere else if needed. Don't go in at night until you've upgraded your equipment a fair bit and have a better feel for the area. Mace is very nice for the swamp. Take in the best food you can and make poison resist potions when you can.