I am truly sorry to hear of the difficulties which you and your mother face.
When you applied to Oxford last year,
(1) did your school mention the circumstances you describe?
(2) did Oxford make you an offer?
If (1) yes, and (2) yes, I assume that you missed the offer. You could contact the college which made the offer, explain how circumstances weighed on you between January and June of this year and ask if the college will still accept you.
If (1) yes, and (2) no, then Oxford has already decided that your circumstances were not sufficient to support admitting you to the university.
If (1) no, and (2) no, you will face an uphill struggle to obtain an offer with A*BB, but, if you and/or your school can put forward a compelling case as to your circumstances, you might have a chance.
Re-sits may be your best option.
Good luck. I hope that things get better for you and your Mother.