So sorry to read about what you are going through. But ask yourself, if you do everything they want you to do you think that will make them happy? I get the feeling that nothing you can do will ever make them truly happy, so why not start living life for yourself?
Maybe write them a letter, explain how they make you feel, and ask them to give their support to you to pursue your own goals. No wonder you don’t feel any ambition; because you are being pushed down a road you don’t want to live on. Neither your parents or yourself are happy with how things are currently standing anyway, so why don’t you at least allow yourself some happiness?
All the best, I hope things work out and they start giving you the support you deserve as their son. Xx