NANNY DROP

I spend the whole week counting the days till I see my one and only grandaughter (aged 14 months) at the weekend. Once the visit is over I go into 'nanny drop' like a mega sad depression, on the edge of tears, heart heavy like an elephant is sitting on my chest, knowing I have to wait another week before I see her again. I dont know whether this is normal and all nans get the same sadness when their grandchildren leave, or is it because I recently (3 yrs ago) lost my other daughter, she died aged 30 suddenly and unexplained, so am I transferring emotions onto my grandaughter for my lost daughter? Ive forgotten what normal is now after such tragedy of losing a child, its hard to find reality benchmark. Its like she is my only ray of light and happiness, when I am upset and crying about my daughter I only have to watch a video of my grandaughter to make me smile again. Poor hubby has to deal with sulky me after a lovely day visiting as I fight off the tears (or sit in the loo for an hour having a secret cry), surely not all nans do that, or is it just me?