Please i need advice

Hi everyone. Im sam and im an alcoholic/addict.
I have a year and a half sober time and now lifes thrown me a curve ball .
I kinda always knew this was going to be a thing but the reality is so real right now .
My boyfriend who ive been with for 3 years has a 2 year old daughter with someone else. Well call her baby girl.
Babygirls mom is an addict too , shes still in active addiction and baby girl lives with her grandmother..
Within the last few months my bf has taken full responsibility for baby girl because mom finally admitted she was his . We always had the idea but it was never confirmed until now . So of course my bf wants custody of babygirls . So do i . But the issue i have is shes very speech delayed , she dealt with abuse and neglect from the mom , in September the mom just left her at the grandmother's and didnt come back . Babygirl has a lot of issues. Shes beautiful and funny and has such a personality but most of the time shes screaming bl**dy murder anytime she doesnt get her way , woth anything, eve things that are dangerous like running in the street.
I have two girls of my own , 5&8 . So their a bit older and understand danger , i dont know if i have another toddler phase in me ..i know that sounds horrible but im still struggling to get my head back together and get my health right . I dont know if i have it in me to take on all this responsibility.
Again i know that sounds horrible but i have to be honest. Half of me just wants to take it day by day , one minute at a time. But the other half fully believes i cant do this right now . I dont know what to do . Im so torn. Im scared , im beating myself up for not being stronger and i just need some advise . Anyone whos been through something similar? How do i navigate staying sober and raising a he*l raiser of a child woth so many special needs ?

I suggest trying the NewForm app! It has helped me so much in my recovery journey (on Memorial Day I’ll have 18 months)! NewForm hosts a virtual Sober Moms meeting and maybe if you were able to tell your story there, there will be other mothers that are or have been in your situation and can help you. And if not at least you have a safe space where you can vent. The opposite of addiction is connection!