Does this mean you're also losing your job, house, car and will be living in B&B accommodation whilst dependent upon Food Banks and undergoing treatment for a life threatening illness? If it does, that's very sad, but you will get through it.
If it doesn't and you still have your home, a job of sorts, car and health, then, realistically, you're looking at an unplanned change of school to one you wouldn't choose if things had remained as comfortable, but will save you so much money that you'll notice a significant improvement to your finances now you aren't tied into handing over thousands every year.
We get kids coming from private (and a small number leaving to go there) throughout the year groups. It's pretty much guaranteed that there will be a batch towards the end of Year 9, a large contingent for Year 12 and then another group coming in the next year to repeat Year 12 with different subject choices. They all settle in fine, and this isn't a fancy state school in the slightest, especially compared to the new all-singing and dancing academies that have opened over the last few years.
It's always hard when things seem to go wrong, but without a stack of things all happening to you at once to the degree that I suggested at the start of this post, the reality is that Everything Will Work Out.