My entire life is a lie.
Why do you feel as though your life has been a lie?
One of my friends told me so.
If you feel like your friend is right, then you need to make a change so that you feel more authentic. You should be more of yourself.
I am not sure how I should change anything.
Maybe you can start with talking to friends and family more. If there is anything you are hiding, you can tell a trusted loved one, or see a therapist to unlock more of yourself. People go through things like this all of the time.