As post above noted, wraiths mostly come out at night. Never be in the swamps at night. You should have enough cores, eyes and fine wood at this point to make a portal home. You can also camp out at the doorway of a close burial chamber at the edge of the swamp. Those work great as portal hub until you can find a building in the swamp to take over or build up in one of the indestructible trees. Use the hoe to make paths all over the swamp so you can keep out of the water but can shoot the leeches. Don't get in the water with them at this point. Carry both health and stamina meads - and of course poison one should be "up" at all times in the beginning. And read the other threads recently posted. Lots of good stuff in them.
Travel safe.