I have a baby but still jealous????

Mi

It took 4 years of treatment and lots of $$$ to get my amazing baby girl. She is 3 months and perfect in every way. Why do I still feel a little jealousy when I hear others announce their easy pregnancy? My co worker has been married for 6 months and they are already pregnant. When i heard i immediately started wondering how they got pregnant so fast. Why do I still feel this way when I finally have my family? Why can't i be happy for these lovely ladies? My infertility was not their fault.