That's a pretty tough one as everyone is different. I had 3 friends in the last 2 and a half years have babies and then a 4th told me at the start of this year she was expecting. I was extremely happy and excited for her but so sad and also a bit jealous cos I wanted it so much to be me. I actually told her that I was really happy for her but also jealous. I never stopped speaking to any of them though, I loved actually going through the pregnancy with them. I guess it was the next best thing IYKWIM. All I can say is try not to feel guilty, maybe send her a little card in the mail inviting her for a coffee or something? Lotsa luck