We went through this as well, but it was done by mid October and now she is in love with her school. I am sorry you are dealing with this; I know how hard it is.
My daughter found her groove by joining two clubs. One of those clubs is her favorite thing in the whole world and has brought her very very close to a smaller group of people ( although not small- maybe 200 students). Some of those kids have become very very close friends. She also started accepting invitations from other students in her classes- to see guest speakers, etc. Additionally, she went for counseling and has a roommate she loves ( that is huge). I have to add that joining these clubs was not easy- it was a competitive process. Had she not gotten in, the outcome in terms of happiness would have been very different.
When my D was misersble I told her that we would re-visit it at Thanksgiving. If she still hated it then I would allow her to send out transfer applications ( was not even sure when those would be due). Then, once those acceptances came, she would have another opportunity to assess the situation again and decide what to do. This gave her 100% control over the situation and seemed to have been a big help. Good luck to you - this is very difficult.