coal

Non-Muslim parents forcing one to worship the dead

Q: I am reverted to Islam and used to be a Hindu. I do not worship idols but during some days Hindu people worship the dead people of their family to show them respect and for that they burn something like coal in name of them and prostate in front of them. I am secretly following Islam and my mother told me to prostrate in front of that even though I was a Muslim, I just sat down and took my head down. I did not touch the ground with my nose and head and was taking name of Allah. I cannot say no to my parents. Have I done shirk? I even cried after this in front of Allah and I am now feeling that I do not deserve to be a servant of Allah. What can I do now?