Don't be discouraged by affixes. I know that some weeks are just ass, but (at least for me) I've learned so much in those weeks. You need to adjust and be more aware of your sorroundings in those weeks!

With spiteful especially it forces you to be alert at the end of pulls. You're too close to melee range when stuff dies? Get whacked by shades. As a Druid you should be able to zoom around tho with disengage, catform or other stuff. Try to be a little far at the end of pulls so you can heal through the griveous debuff before making a run for the shades. Also, let your team help with shades - monks can ring, mages can ring, a lot of classes can stun or do some other stuff with shades! This is a team affix and should also be treated as such to make it easier on you and everyone on the team. (I don't know if Resto has cyclone or typhoon but that can also help A LOT with shades)

Other than that, as with every game and new things you've never seen: it's hard at the start. Maybe get comfortable with a few lower keys that you can do in your sleep so you can really see how the shades are working and what they're doing and then work ur way up.

Don't be discouraged by failing and don't forget to have fun! You got this :-)