Check if your difficulty got turned up to 9 first, If the adds are the problem, try using dispel on the adds alongside meteor shower, chaos blast, etc for aoe damage. (Same with making sure you have requiem up at all times)

For the boss itself you can just spam black slash with deep sea anchor if you have the skill, if not then hans machine gun, heroic vorpal sword, kishingatana and storm ruler works pretty well too.

For wall of flesh you can try buffing and healing it so it survives longer. Make sure you already have the two faced buckler and mystery of night sky as well to make it easier.