Cute but weird

So I'm not pregnant yet (that I know of, haven't tested this month) but my boyfriend keeps wanting to lay on my boobs and rub my tummy and kiss it. He keeps talking about a baby and such. Also my little brother who is 18 months old has recently been waaaay more clingy to me. And he keeps wanting to lift my shirt and touch my belly or just cuddle up with me. He has always been attached to me but never like this. He likes to play but never actually sit and cuddle me. He also keeps saying "jie jie, baby" (jie jie is mandarin for older sister, said kind of like j-j). Idk I'm kind of nauseous but I don't know if it's cause I'm thinking about it. But other than that no symptoms. No sore boobs, no excessive peeing.. I don't know when my period is due as I am super irregular.