Miranda, here is my advice on what to do:
put "sorority" in your rear view mirror. You've had two bites at the apple. You rejected one house twice. You'll likely not get any other chances. We (actives and alumnae) talk to each other, despite all the "rank" or "tier" animosity promoted on other sites. We look out for each other. And your rejection of one house, twice, speaks volumes to all of us. I am sad for that house, particularly. Twice they wanted you to be a sister. Coming from this side, it hurts us too.
I respect your right to reject that house. You had your reasons and that's why you are here, bidless, asking what you can do. There is nothing I can say to change your view of your situation and yourself. I'm very sorry for you, that you gave up the opportunity to discover the meaning of what we alumnae know: membership is for a lifetime. Additionally there is a Panhellenic bond that we talk about frequently here. I have an instant connection with other sorority women, not just with other Thetas. I consider many members of this forum to be my friends (and you guys know who you are!
).
Dealing with this disappointment, hurt, and rejection is your task now. There are myriad organizations on and off campus that welcome active participants. First things first: give time time, and don't look for a replacement for sorority membership (not sure what that would be, however, or even if there is a replacement) until you've accepted your situation and moved past this stage. You may benefit from some counseling; we all can use life coaches and most people I know do so. I wish you the best.