Being a single parent Granparent

I am wondering if anybody else has experienced he difficulties I am currently going through. I have one adult child, DS, who is married with a two year old and another on the way. I brought him up on my own, with an enormous amount of help from my parents. Both may parents passed away approx 8 years ago, only 7 months apart. About a year after that my son went to live/work abroad with my encouragement. 5 years later her returns to the UK married with a baby on the way. Shortly before my parents passed I met my partner (who has no children). Since my son and family returned and live locally I have really struggled to settle. My GD looks so much like my son when he was tiny, she brings back floods of memories, and often this makes me quite melancholy because I realise I've no-one to share those memories with. Family life with DiL has been tricky. My partner tries to be as empathetic as possible. I thought the hard part of single parenting was way behind me, but I am shocked at how hard I am finding this new family structure with me as Nanna. Does anyone else have any experience or understanding of similar circumstances? Thanks for listening.