Maybe stick it out for just a little bit longer? It sounds like you a feeling a bit tentative. How do you like your pledge class? If you like them, perhaps wait until you have bonded a bit more with people before deciding anything rash, or that you cannot undo. I don't know your campus, but I think that if you were to decide to depledge, I don't know how easy it would be for you to rush another NPC group the following year (you might be something of a "marked woman"...sorry to say that, but rush has some not-so nice sides to it). Also, in the long run, Chi O is a very large sorority and this could come in handy if you were to move cities and you didn't know anyone. You could make friends with other Chi O's in the local alum chapter when you got to your new city.

Whatever you decide, I hope that it works out for you. Maybe there are some Chi O ladies who could offer you some advice.
You are definitely in a tough predicament. Good Luck!