Struggling a bit with jealousy!!

Am I the only one who feels like everyone around me is expecting or just had a baby?? My SIL is expecting her first baby in December.. I'm super happy and excited for her but I can't help but feel twinges of jealousy when she puts sonograms and baby shower ideas up.. I just want to know I'm not alone in feeling this way!! Having a tough time ladies!! Talk me off the ledge!