Your bonus healing is pretty good for you level. Getting to 64 and lifebloom will change your healing drastically but until you get to it, the best way I found to do it as I leveled was this:
Throw a rejuv on the tank before he pulls. Emphasis on before. When he pulls the healing will count against him as aggro and not you. You have to do this before he shoots, face pulls, charges the mob.
By the point you should know how much your regrowths are typically healing for and you can go ahead and start casting one when the tank has taken about half that in damage. That way when it does hit 2 seconds later you’re not overhealing and at that point he’ll have the HoT from the regrowth and the HoT from the rejuv on him.
I did that pretty much exactly that way from the 30′s in SM till the 60′s in Hellfire and Zangar.
Just wait till lifebloom 
You’ll throw a 3 stack and a rejuv on the tank and /dance 3/4′s of the time.-Galenmoon – 80 Feral Drood
Gavinitis – 80 Shammy
“OH SHlT SON ArexYour +healing looks like more than enough to heal either of those instances. I’d suggest try to keep rejuvenation up 100 of the time, if he falls a little fast use a regrowth + swiftmend (both can crit so it can add up to alot).
Also make a Healing Touch + Nature’s Swiftness macro. Being able to land a full HT instantly can be the difference between downing that boss or running back to your corpse.
You should be doing just fine, might just be a little practice needed. If you keep struggling it might be time to turn the eye on the tank and see if he’s adequately I’m just curious if I should dump some stuff or pick up an item I may have missed. I actually had a pretty rough time doing Blood furnace with just a bit lower +healing. I don’t have the bloom yet and my ticks seem to be a bit slow. Usually I drop tree form and have to bust out the healing touches and that frustrates me.
