Jokes aside, without Heirlooms you're gonna get stepped on around that level if you're not in blood spec. I remember doing a few BGs while my DK was leveling and I just got raped by ranged and melee alike.
If you don't go blood run frost but it's not balanced at all and you're just gonna get frustrated.
I can only advise you preservere without heirlooms until level 70. Save ~800-1500 honor and buy yourself the brutal gladiator's set. You're going to be on pretty much equal footing from then on.