I am 27 weeks today and so far have put on, at the most, 2kgs. And that is with the last 6 weeks being mostly bedrest. Bubs is growing fine and when I asked if I should be worrying about the weight not piling on, my ob just said to count myself lucky. He said as long as you start the pg at a healthy weight (ie not dramatically underweight) then the baby will take what it needs from you.
Also, depending on where your placenta is sitting will affect how long it takes to feel movement - mine is at the front so I felt her later than my SIL whose placenta is at the back.