Stupid question.. sorry

So my boobs are sore and way too sensitive, they hurt. And having some weird light cramping more of a feeling full feeling. My AF isn't due until either the 13th or 18th.. but anyways my friend just had her baby and it's so weird the smell of baby Quinten made my boobs feel like they were pulsing like blood flow/ heart beat type pulsing and when he cried I felt like my boobs were about to explode from the nipples.. similar to when I had my daughter or when I was pregnant with her.. and now I'm having pinching pains right by my belly button like a wee bit above my belly button.. is this normal for if you've already had a kid (my daughter is 5yr old) this is the first time sense my daughter that my body has reacted to a new baby like this,, that I can remember, does this happen to others who have already had kids?? Or is there any ideas what this could be??