Collecting your corpse/items gives you a buff called "Corpse Run" which (if I recall correctly) decreases stamina consumption, buffs your defense, increases health regeneration and increases run speed slightly. It's meant to help give you time to get away from direct contact with enemies and equip your gear. It's not a fool-proof solution, but it helps a lot. My advice is to drop everything so your inventory is completely empty and then run and grab your corpse. It will auto loot everything very quickly (assuming you weren't encumbered when you died) and allows you a quick escape. Dying near a crowd of tougher enemies makes this a tougher thing to do, naturally.