What is the religious ruling regarding my situation, and what advice should I follow?

If you were burdened with this responsibility, then it is an injustice, and you should seek forgiveness for the deceased and forgive those who remain. However, if you bore it voluntarily, you will be rewarded for your intention to honor your parents. Thank Allah for your status in your home, and ask Him for a righteous husband. Seek your reward from Allah, recite the Quran, make abundant supplications, seek help through patience and prayer, and pour out your worries to Allah as Jacob (peace be upon him) did: "He said, 'I only complain of my suffering and my grief to Allah, and I know from Allah that which you do not know.'" Your siblings should help you with these burdens.