Mortaff, from your post, I think what is making you so unhappy is not the lack of excitement and love in relation to your grandchild, but rather your own expectations and feelings of failure. Not every woman wants to be a mother, so inevitably, not every woman will especially want to be a grandmother. You do not have to love this child s/he does not need that from you. S/he need their parents to love them. So long as you smile and say nice things, give gifts at appropriate times etc, all will be well. Choose a 'nana' type of name that you are happy enough with and say you would like to be called that. Tell those concerned that you don't want to be called 'granny'. It's not unusual. Remember that the mother's mother tends to be the favoured grandparent (all things being equal) for visits, babysitting etc, if they too live nearby. This often causes upset, but it won't in your case and that will make for much easier relationships all around.
You are not the only one who feels this way. I have two daughters and a son. My son is estranged since I divorced his father. That broke my heart for years. When it happened, he had a 1-year-old that I had only seen on three occasions (daughter-in-law's mother had lots of visits and she lived around the corner to us). I grieved hard for the loss of my son, but I hardly knew my grandson, so not seeing him after the estrangement didn't really bother me. My son went on to have two more children. I found out about them from one of my daughters, who discovered it on Facebook (he cut her off too). My other daughter didn't bring it up with me because she didn't want to upset me further. So many people assume that the most difficult aspect of it all is having no contact with those grandchildren. This could not be further from the truth. I don't know those children, so I feel nothing for them (cue horrified gasps). I wish them well as I would with any child. Otherwise, nothing. My oldest daughter has three children who I am very fond of and have lovely relationships with. My youngest is just expecting her first child. I am surprised to find I am more interested in her being pregnant (maybe because she is the baby of the family?), I am looking forward to the arrival of this child. I may find I love her/him, but I don't expect to become the archetypal doting grandmother.
Just let it be what it is. Be kind to yourself and to your grandchild and everything will be fine.