"I am terrified that this money will never be returned"

I am a UK resident and taxpayer. I deposited a considerable sum of money (well over £50,000) to generate interest to pay the fees for my 92 year old mother's residential care home. My mother has no idea of this situation, thank goodness but I can only continue to pay the bills for a while longer.
I am terrified at the possibility that this money will never be returned and don’t allow myself to think about it.