Breastfeeding and smoking

So I just had my son a week ago and I smoked weed last night for the first time since I got pregnant. He’s formula fed because I didn’t have a breast pump. I just got a pump and I want to breastfeed but I want to quit and make sure it’s out of my system before I breastfeed.. how long will that take? I wouldn’t of smoked if I knew it passed thru breastmilk. He hasn’t fed yet and Cannabis is legal here, I went outside and showered and changed immediately so please don’t judge me