I levelled as affliction in full Naxx gear and other equal quality epics. Wild stories are told about soloing 5 mobs and never having to drink, though they are not true. In a pack of 5 you have to eat/drink after every pack and will overall be slower. You can do 2 mobs at a time and never drink, or 3 mobs and occasionally drink. That is in full T3 epics, with lower gear it will probably be a lot worse.
Howl of terror has a 40 sec cooldown, which makes it an invallid tactic, plus you will be running all over the place to pick up loot, slowing you further down.
In regard to having just levelling gear, felguard seems best to me.