Looking for an up to date necro guide.. also why do I keep dying for no reason?

I've decided to dust off the necro and have forgotten many things about the class like what are the best AA trees, casting order, also what blue stats to focus on, what adornments to get, what to cast for group encounters vs single, any info really..

Also I noticed a couple times, once in tranquil sea, and once in Skyshrine my character losing health and power very rapidly (without fighting anything) and me having to heal through it or zone a few times until it goes away. I thought it was Lich at first but I clicked it off and it was still the same though lich made the health losing portion faster.. It's been 2 expansions ago that I played my necro so did they add something I am not aware about? Because it doesn't happen all the time and I dont remember doing anything different just that I kept losing health and power.

thanks in advance

I don't actually play a Necro but I think there is a buff which prevents your pet from receiving AoE damage that also drains your health and mana whilst it is active?

Bloodpact, it drains HP quite significantly out of combat.

Thank you! I was going through all my abilities and didn't see anything and also since it didnt happen all the time I couldnt figure out what the heck was going on

want some real fun get an ev charm or have someone cast ev on you ohhhh and watch your HP fall....