OP, she sounds just like my 2nd. You don't need to see any physical or outwards signs of love at this stage, believe me, she adores you and you are her world, no actually, you are her universe.
My 2nd was a funny little baby, never really smiled at me, just stared a lot! Because I was a second-timer and was more confident, I didn't notice this until I looked back. She is my shadow now and has been since she could communicate. She, literally, puts me on a pedestal (bless her, I dread to think what a disappointment it will be for her when she realises I'm not superhuman).
Might you have have some underlying insecurities? I remember before I had my eldest, I felt a little 'unworthy'. I watched my sisters, cousins, friends etc have children and saw how brilliant they were at parenting and how much these children loved them.
I didn't think I could be as good a parent and I worried that my kids wouldn't love me as much as my family's/friends kids loved them. To my surprise, I found that I could be just as good a parent and all mine are totally clingy to me and think I'm the best thing since sliced bread.
This adoration would normally be hard for me to feel is deserved but I put my everything into being their mum, I sometimes get it wrong but I try my hardest and they know how much I adore them. I love being a parent, it has highs and lows, no matter what age they are but your kids will ALWAYS love you.
Do remember that the baby stage, although it feels quite long, passes by quickly and I think you'll forget that you once felt this way as your baby grows.
Try not to worry too much, or look for the signs, they WILL come and when they do, even though you'll have heard 'Mummy, I love you' for the millionth time, you'll still feel blessed.
It's the 'muuuuuum, I can't find my shoes, or the 'MUUUUUUMMMMMM where are you?' (said at the top of their voice, whilst you are trying to have a wee in peace) and 'muuuumm, this food that you have spent 3 hours cooking is yucky' that gets a little wearing. 
