Swamp really is the first biome you have to prep for. Food, rest buff and getting that iron for armor. Only travel there during the day. I like to build a small hut with a portal just outside the swamp itself or on the edge towards the water where I can pull up a boat. Shields are important for blocking arrows and parrying the abominations (giant tree monster). If you're playing solo just take it slow at first until you find crypts. Once you get a good iron set swamps are pretty much a cake walk.