Struggling with addiction during pregnancy

I’ve been prescribed medicinal cannabis for a pretty long time to help manage with my mental health. When Finding out I was pregnant I took quite a long time making my decision. I decided to continue with my pregnancy and began trying to quit using cannabis. I’m not proud at all of my actions but I have continued smoking so far (I am 17 weeks pregnant) I still intend fully to quit but I’m finding it so hard on my mental health and physical health. I of course carry so much shame and am not proud of how I’ve dealt with my pregnancy the past 4 months. I just really felt like I needed to share this and if anyone has had experience with addiction during pregnancy I would love to hear your thoughts