why do I feel like this

so for a while now all I want to do is become a mother, my mum passes away 2 years ago this March and it's been really difficult.
My partner and I have been together for 2 years and we have our own home and we love each other...we talked about trying for a baby but he changed his mind a few days later, then he wanted to try again but changed his mind AGAIN
It's stressing me out, his sister just had a baby, I love her so much she never cries with me and I'm really good with her, I love babies/kids so much and I get so emotional that I don't have one and that my man doesn't want one yet.
Why do I feel so strongly about becoming a mum like right now, all I want to do it like talk about babies and kids and buy baby shit like I bought this cute little bear towel with ears and I've hidden I away until I have a child...is that weird? like what's happening to me :(