Hi there ~
I understand your concerns. Being pregnant for 8 1/2 months and using meth regularly is probably going to have some kind of effect on the baby. I believe that you need consult a psychiatrist
as soon as possible and let your OBGYN
know that you have had problems with being dependent on methamphetamine
so as to treat your newborn for withdrawals and prevent any kind of issues that you may have as well after childbirth. I also believe that you need to have your sister be seen by a medical doctor
now and as soon as possible.
I hope this helps. Take care and have a lovely day!