I’m a recovering addict and I think I’ve done the craziest shit

Quick backstory. I’m a recovering addict. I’ve been to rehab and it didn’t really help me. And I relapsed and I’m going to rehab again tomorrow. I have a boyfriend who has been uncomfortable about my addiction but when I relapsed this current time I didn’t tell him. He had always been scared of me getting pregnant with another mans baby and he doesn’t even know he’s not the dad. I got pregnant about 7 months ago when I was on fentanyl but I didn’t know I was. I always thought I had a period because of the bleeding from fentanyl. So I found out I was pregnant and it was way too late to abort it. So I went to rehab and got clean and had my baby girl. She was a bit premature and didn’t have any complications from the fentanyl but when I got out and brought her home and had to take care of her I would be so paranoid and scared. I had to drive myself to therapy and go grocery shopping with her alone and I was just so scared. One day I had to take her to a doctor appointment and I was so shaken and I didn’t know what to do so I asked my ex if he could take care of her and he agreed. I told him I relapsed and didn’t know what to do and he said “wow, you’re doing awesome” and it just made me want to cry. I sent him her birth certificate that had her dad name and she wasn’t named after him. And he asked if her dad was around and I said no he’s in jail. So now he’s taking care of her tonight and tomorrow I’m going to rehab and I just don’t know what to do. I don’t know if he’ll ever find out but I don’t want him too. I’m uncomfortable with my past and don’t know what to do.