Litigation with loved ones over real estate. What should I do?translated

Reader question:

Two years ago I planned to take out a mortgage. My sister said that then we would sell my parents’ apartment and divide the money: the main part would go to my mortgage, the rest to my sister and parents. I was indignant that she presented everyone with a fait accompli. My sister was offended and said that I shouldn’t take out a mortgage. Mom took her side. Then my parents offered to give me their shares. I didn’t agree right away. As a result, I gave money for the down payment to my mother and made repairs by taking out a loan. I put off making a donation for two years. This summer I suggested that my mother go to a notary. The sister was offended and said that her mother was depriving her of her inheritance. Mom talked to the priest, and he did not bless the gift, saying that making promises is not Christian. But it was an agreement, not a promise. Now everything is cancelled. I live in an apartment where I own 1/3, and I pay a loan for renovations. My sister said that I need to marry a man with housing, and if I don’t go out and buy an apartment, then “of course she won’t kick me out” after the death of my parents. I agree that the apartment is a common inheritance.

But then there was no need to stop me from taking out a mortgage and getting my hopes up. How should I approach this situation?...