Needing help please!

I found out my son has a milk protein allergy a few days ago.. he's only a week old i was trying to breastfeed and i am giving formula.. before we found out that it was a milk protein allergy my pediatrician had asked me to stick to formula until he was seen so i did after he did some tests he put him on a different formula.. I had forgot to ask if it would be okay for me to start breastfeeding. I have been pumping since i was told to stop.. my question is is it okay to start giving him my breastmilk?? Is there anything i need to do??