advice/help needed

so I'm having some weird problems...for the last couple months all I seem to want is a baby, to start a family...my boyfriend and I started to try but then he changed his mind and it's made me really emotional and upset that he jus changed his mind like that.
His sister has a baby who is 6 months old and every time we see her I want one more! 
I had a miscarriage with my ex a couple years ago and I've always had a small crack in my heart from it.
I've been trying to talk about having or trying for a baby with my man but he just thinks it's annoying that I talk about it everyday.
can someone give me some advice on how to deal with these weird feelings?