Madge I should say I did struggle in the very early days with DD (birth child), I was quite ill and stayed in hospital longer than normal. I did not start to bond with her until we got home (not properly) it was only about 11 or 12 days but after waiting for so long...I wanted a child when I was much younger... I too was 39 meplusone... it was interesting I did not really feel that rush of love early on. She was ill at birth (briefly) and having worried I might not carry to term (with some cause) maybe I was not ready to let myself love her!
DS came to us aged 3 and I loved him quite quickly, but it was a shallow kind of love. It came quickly but it could go again quickly, when he pushed my buttons, as he does, and as dd does, daily! I think now that love is more secure but it has taken almost a year and sometimes I still feel we are on that journey. I had nine years with dd before ds arrived so it takes a while to make that love as secure as it can be, and they challenge me all the time, both of them, pushing me away and drawing me close. That is why those times when they are shy, or scared, or ill (not that I want those times, God forbid they are terrible) yet in those moments we draw close because they need me and I need them to be OK.
There is a song I love.... Love is not a feeling (it says Love is not a feeling it's an act of your will). It's a Christian song by Don Francisco (I am a Christian) I am not sure it is relevant here, (Google it if you like) but I do believe love is an act of your will. And when you act lovingly you feel loving and you feel love.
I must say at times I need to remind myself with both my kids that to some degree I am their world and when they are rude or naughty etc, actually it is because they know I love them and they know they can trust me. And all those loving things we do, build that love. It's not just loving words, they would not make much headway if the actions did not back it up. 'I love you' but there is no warm bed, no nice dinner, no care when they are sick etc. You give all that love whatever you feel (I am sure you do) and when you feel less loving you fake it in words because you are making it already in actions. (I feel sure you are because all of us have been through so much to parent, how could we not!).