Has anyone quit smoking during pregnancy? Any help?

I've been a smoker for 10+ years. The fact I even got pregnant feels like a miracle. After I had one miscarriage I was devastated but quickly found out I was pregnant again. This time I want to ensure it doesn't happen again....but I'm having a really hard time quitting altogether. I've been cutting back but I still feel like an awful mom who isn't good enough. It makes me disgusted to say but I haven't been able to kick it...any ideas thoughts suggestions that might help me?