Citizenship through Marriage

Sir, I migrated from Nepal to India with my father at a very young age.I lost my parents afterwards in Assam.Later I married an Indian girl and have Kids too. Its almost 40 years to our marriage. I don't know any whereabouts of my Nepali origin nor I have any official records about my origin. I have grown up throughout in India.I do hold a Indian passport on the basis of addresses of my the properties owned by me after 1972. I don't have any official documents of staying in Assam prior to 1972.But I have been voting in Assam after 1972 and my name is also in the Voter's list. But recently Assam Govt. has decided to update its National Registrar of Citizenship(NRC) and due to which they asking for any parental origins, or documents of residing in India before 24th March 1971.Sadly I don't have any records. So I am not being able to register my name for NRC up gradation ,failing to which I will be considered an illegal foreign immigrants. I am in great anxiety about my existence now, I have already used my Indian Passport registered in Guwahati for various foreign tours for which I may be punished for illegal Passport too but I am not any illegal citizen as I have lived throughout my years in India. Please help me. How can I overcome this legal hurdle? Please suggest me.