Even though the land was not formally signed over to you, my view is that your parents hold it on a constructive trust for you through the doctrine of proprietary estoppel. This means that where B does something to his detriment which has been induced by a promise made by A, A is then estopped from insisting on his strict legal rights. Thus your parents said "here the land is yours", you put every penny into building a home so they cannot now insist on their strict legal rights. Get legal advice asap.