HELP!!!

My SO might have a baby!!! I'm upset, this kid will be his first kid and I wanted our baby to be both of our first but now this shit! I'm just hurt cause I'm having such a hard time getting pregnant and I've been so emotional ..... then he springs this shit on me! He said it happened while we was broken up but he's just NOW telling me and the kids a few weeks old! I'm hurt and I think I'm being selfish but still, it's upsetting to me cause this is gonna change us! Idk if she's a crazy baby mama or what's she's gonna do to him IF it's his! I just hope it's not his!!!