Reading the background, GrannyT I am not surprised you are finding it difficult to feel anything for your first GC.
MY DS and DDiL were married, had had to leave forming a family until quite late and all of us wee over the moon when we knew a baby was expected. But when she was born, although I was excited by becoming a grandmother, I didn't immediately feel any bond with the baby.
Possibly because DGD was a 'screamer' and I was so tied up with worrying about DS, and especially DDiL, pacing the floor all night and feeding all day, both exhausted, that DGD was, initially, more a disrupter of family life than a blessing, but within 6 months, DGD had calmed down (a bit), life on all fronts was easier and she just became part of the family as loved as everyone else and like most grandparents I had reached the stage of being besotted by her
She is now 10, coming to stay for half term and I cannot wait to have her with us for a week.
Your circumstances are difficult GrannyT, I am not surprised you feel as you do.