Hi Liv, welcome to SR. I'm an alcoholic, sober now, and the thought of giving up my best friend was really scary. I motivated myself by looking forward in time, working out where my path was taking me. It was scary; damage to my body and mental health, turning into the sort of person I never wanted to be. My life isn't perfect sober, but it's like a huge burden has been removed. Whatever else goes wrong, I don't have that worry any more, and I love that I had the strength to leave my 'friend' wine.
You have some motivation; how can you get more? What do you fear most about heroin addiction? Where will you be 5 years down the road? Where is it leading? Will it stop you having children?