Auto heal not working

Hi. I need help. I dont have any heal item like panacea fan or umbrella but i use vernal umbrella and nameless sword. Before this, everytime i dealt damage fighting enemy, my health will restore automatically 3-5 seconds after it ends (all the enemy died) but now im not sure what change, the auto heal did not effective anymore.. can u guys help which inner way or gear maybe i have change and need to change it back?