It is natural the amount of angry responses you are getting on here. For most of us, we would never do anything to harm our babies and do everything to protect them, so what you are doing seems unfathomable. I'm sat here with a baby in my tummy worrying about whether I've eaten enough protein today and would deliberate back and forth about having a glass of watered down wine with my meal at a wedding.
I also know there are some terrible walks of life that many have just never been exposed to. I'm related to a heroin addict who used throughout her pregnancy. On the outside it is unfathomable. But those closer to her had more insight. She'd been raised in the care system. She'd been prostituted out since the age of 13. She lived in a bed sit with no wallpaper or carpets. She used because that's all she knew. Her baby died a few weeks after birth, by the way. Nature didn't show any sympathy for her difficult past.
Rather than give you an angry rant about what a terrible mother you are, because I know that won't work, I have some questions for you.
Who are you using with? Someone is doing the drugs with you right? Then why are you in their company? You know they don't have your best interests at heart, right?
Or are you using alone? How long have you been using alone? And why?
What is your plan? You keep repeating the same mistakes so what do you need to change? Can you change and do you want to change? You can't wish change into existence so what are you going to do about it? And if you don't want to change, then what are your plans to keep your baby safe once they arrive?
What's the underlying cause of this destructive behavior? If not addiction? Then what? Most people don't just go around fancying a bit of coke in pregnancy. So what makes you the outlier? What deep down inside of you is causing this behavior? Is this a demon you want to live with for the rest of your life, baby or no baby?
Have you ever been to an AA meeting or similar? What's stopping you from talking about this with a real person? Or a real group of people who have been where you are now and come out the other side? What's stopping you from getting their perspective?