Its definately not gas...I feel when I have gas and when the baby is fluttering around. Its a totally different sensation.
Even in the u/s I was feeling it and sure enough he was flopping around. After I sneeze of cough I get a little mini flutter feeling kick...super light.
It has never been a huge "jerk on the inside"... the flutters for me are right at the front of my uterus about an inch or two below my bellybutton...where as gas would be deeper in my tummy as the uterus is infront of the intestines and bowels.
If I am busy and going about my day I dont notice anything, its when I am sitting down and things are quiet etc that i can sense it.
I am sure as this little nugget gets bigger I will feel it nomatter what I am doin.
thx 4 sharin ur experience though!!