On the pill/Sex after delivery

My son is 1 month & 3 weeks old. I started taking the pill a week and 4 days ago. My husband and I had sex for the first time yesterday without any other kind of protection and I’m worried I could be pregnant again, because I’m not on the second week of the pill yet. The pill information paper said you have to wait 2 weeks to have a full protection. 😕

I know it’s easier to get pregnant right after delivery, so... can anyone tell me if you think it’s possible?

I’m breastfeeding too, so I haven’t had my first period after delivery. And it may not come for a few months, until I stop breastfeeding.