What about a half-day school situation for your daughter? I've seen many a six year old adapt perfectly well to school in a completely foreign language, I must say. A half day might be just enough to gain an immersion setting, and not too much to push her over the edge in terms of fatigue. Learning a language is exhausting! Also, most schools here have ESL programs for children.
Obviously, you know your child best, and I'm sure she'll do wonderfully if you just continue on with what you're doing. Just don't cross school off the list, because it could work if you guys wanted it to.
I'm so sorry you're lonely. I remember that crushing isolation when I first moved to Latin America, and it certainly isn't fun. Hugs to you. It will get better though. Where are you, roughly? Have you checked the Finding Your Tribe part of MDC? I've never lived in a place where there are other MDCers, but if you're in part of the Maritimes, Ontario or BC, chances are good that there's a "real life" MDC contingent near you!
Hang in there.