There are hundreds if not thousands of posts just like this one all with people giving the exact same advice... over and over and over and over...

-Avoid exploring an area if you get instant killed there. Its too hard. Come back later.
-Always place a portal before exploring a new area, it makes corpse/recovery runs much easier.
-The biome progression is meadows -black forest - swamp- mountains - plains -mistlands.
-Sometimes you have to cut your losses.