Buspar and breastfeeding

[B&E]

I an 6weeks post partum. I was on 75mg of effexor whole pregnancy just increased 2 weeks ago to 150. I was prescribed buspar during pregnancy which I didnt take. I am having increased anxiety and want to take it as needed like it was prescribed. Is this going to harm my baby? I exclusively pump and feed on demand. My psych wanted clonazepam but on call OB during pregnancy said it had to be buspar.
advice? I dont want to harm my baby.