You have decent gear, but I saw that you had no Tier 9 pieces. Crafted and badge gear is good, but does not compete with Tier 9 set bonuses. This could contribute to the difference you're seeing. I'd keep the chest, and go for a 4 piece Tier 9 set asap. Even tho you're blood, you should see a nice dps increase just from disease damage alone (plus the 2 piece set bonus gives a great str proc as well.) If you get Tier 9, you may want to get Glyph of Disease...it's a great glyph for keeping your diseases up. GoDD I think is better at higher gear levels.
Also you have a lot of wasted Hit Rating with the trinket you have...about 135 over. Plus if you have dranei buff, you may be even more over hit cap. That's a wasted stat and does nothing for your dps, other than the AP buff every 2 minutes. There are better trinkets out there that will provide more dps, even at lower ilevels. Your expertise is low as well, and should be around 26...this could account lost dps due to boss dodges. While I wouldn't gem for it, you could try for the TOC 10 trinket that give expertise, and swap out that Hit one. Also, don't humans gain an Expertise racial bonus by equipping a sword? That may also be something you look in to.
Make a macro that hits hysteria, trinket, ghoul and pops DRW, that way you get the most bang out of your gear. If you can coincide that with one of your other procs, your dps will climb.
