jealousy

My little sister conceived my niece at age 17, when I first started my TTC journey. I hadn't told anyone about trying at the time. I was jealous at first but I love my niece and come to visit when I can. (I moved out of state) Shes about one and a half now. Ive told my family about my PCOS and trouble conceiving. Anyways, I came down to visit my family. First thing my sister says is "I'm pregnant" I was like are you joking? (Since it was April 1st) she said no I'm serious. Then for the next couple hours proceeds to talk about how she's pregnant and blah blah blah and then gets mad at me for not giving her all the attention she wants. My whole time here visiting, that's all my sister has been talking about, how her boobs hurt, how she's hungry, she even had me go baby clothes shopping with her. I don't know if I'm just being a jerk but come on it just feels like a slap in the face.