I've been lying to myself my entire life and it has hurt me and those around me
Why would you continue to do it?
Whenever I lied I would feel guilty because I know that lying is wrong.
In life, one of the most important things you can learn is acceptance. Accepting things for as they are, accepting yourself, and accepting your circumstances.
I just don't know how to be honest.
Since you've been lying so long, you'll need to take small steps. Just work on being honest with yourself and others and you'll see it's possible.