Girls!!

I am really worried. I have been hearing moms in and around my weeks of pregnancy say that they feel the baby move from one side to another, and strong kicks but i have never felt a kick strong enough. Infact my baby's movements have always been less as compared to what i hear others say.
When i consulted with my doctor she said 15-20 in a day is also fine.
But i read and hear people say they feel about 10 moves an hour also at times. Is there something seriously wrong with my baby???
Could the baby be weak??
I am absolutelt petrified. Please help.
I have felt my baby movements only below my navel everytime and very rarely on the sides. And the movements are like kicks not the movement where i can feel the baby moving from one corner to another. What could this mean??

Also at times i feel so light that i dont even feel like i am carrying. Though i get low bp prob and some weakness occasionally but never i have felt heavy or uncomfortable in the tummy because of baby movements or weight. Is this normal.