I gave 11 years of my life to an emotionally abusive friend
Why did you give 11 years of your life to such friend?
I lost myself and my own sense of worth.
You clearly put up with a lot from that friend. Changing your life to avoid such people is what you needed now, just go forward from here with that same frame of mind before you loose your mind completely.
I also dated him.
We can't change the past, but you show a lot of strength that you were able to break free and get out of the cycle of abuse. I am proud of you, but I am worried you might have some lasting scars. Would you like to try talking to a therapist as well?