It is hard. Happened to me. I had a friend due two months before me. And one due the same month as me.. Then my sister got pregnant with her second.
I didn't get pregnant again for over a year... Don't tred lightly. Don't not include her. That it will make it worse..
Its gonna be rough for a bit, my guess is till she gets pregnant again... 2 of my friends were due at the same time and the one lost hers at 7 months so it was rough to hear that our other friend had her baby and she said it was rough that everyone around her seemed to be pregnant... she started trying right away after and was preg 3 months after... she now has 2 boys and with her last one me and her had our babies a month apart... it made me nervous to know and im sure it was in the back of her mind too, adn we both have healthy babys, its just unfortunate that these things happen... it will get better with time and whe she is ready to try again hopefully it happens right away, and she will be happy for you with your baby but understandibly a little sad... but you take care of yourself and dont feel bad, you are allowed to be happy about your pregnancy, just maybe avoid talking too much about it around her as she needs time to heal...
I had that happen to me. I hwas having a miscarriage and it seemed like everyone around me was pregnant withouth even trying to get pregnant. All that you can do is be there for your friend. It will get better.