First of all, your friend does not have a “charmed “ life. She has a life, just as you do. Her life experiences might have been different in terms of loss, but she will have had difficulties, problems, setbacks and anxieties because that IS life and is what happens to us all.
You have lost people close to you, but you are not the only person who has. My father died when I was a child, my mother died when I was in my early twenties, my brother died when he was in his twenties, and I have lost other people close to me too. Sad events -like yours - and I mourn their passing, but it does not rule my life, or stop me celebrating other people’s happiness and hearing about their families without being bitter and feeling slighted and cheated.
Why haven’t you made the effort to keep in touch with your friend and tell her about more recent events in your life, both the sad and the happy? I am not surprised she responded to you with pictures and news about her family, she was trying to update you in a condensed way of events in her life since she last saw you or heard from you. It’s not her fault that her family members are alive, and since you haven’t kept her up to date about your family you can’t expect her to know of your losses and struggles. Or in deed the good things like your daughters degree and your former relationship.
Sorry to sound harsh, I know you are not feeling good at the moment, but I am trying to get you to see things in perspective. To say for example that your friend is unfeeling to post photos of her children when she “knows” that seventeen years ago you were considering ivf is one example of how I think perhaps you are seeing things in a very skewed way. Similarly if you have met her mum in the past it is perfectly normal to send you a recent picture of her,it is not being unfeeling because you don’t have your mum any more.
Please meet up with your friend and enjoy the walk and the renewed friendship, I hope it revives the relationship for both of you, and that you can enjoy revisiting and reminiscing about your shared memories and perhaps eventually sharing more recent sadder and happier feelings and experiences.
Take care.