What should I do about my parents' continuous prayers against me, and my feeling that God is answering their prayers, which is causing me misery and illness in my life?

Supplicating against one's child is forbidden by Islamic law, unless it is due to the children's disobedience and injustice towards their parents. The son is obligated to honor his parents and obey them in what is good. He must sincerely repent for any wrongdoing or negligence towards them, for indeed, the repentant, by Allah's will, will not be punished for his sin. If the son fulfills his parents' rights, then their supplication against him unjustly will not harm him. The matter of supplication's acceptance rests with Allah Almighty, and it is hoped, out of His generosity, that He does not answer a parent's supplication against their child at a moment of anger, because they are invoking evil without intending to do so. If a servant experiences hardship or calamities, he should re-evaluate himself, his relationship with Allah, and increase in repentance and seeking forgiveness.