Weed & breastfeeding

Hey guys, so I have to stop breastfeeding for a while due to my son being allergic to cows milk & since I eat alot of diary it was effecting him so I switched him over to formula.. I ended up smoking weed again due to not me breastfeeding. I want to stop i taking dairy so

I can breastfeed but problem is that I smoked and I know the THC stays in the system for a while. So what I’m trying to ask has anybody breastfeed while smoking or how much can It effect him ?