I wish you the best of luck with this pregnancy, and am sorry to hear that you have had to miscarriages. A fluttering feeling is definitely not the baby moving, most women will feel movement around 18 weeks or later.
There are many other organs doing their jobs in that area of your belly, so it may be only coincidental that you feel a fluttering before you have a miscarriage. When you are pregnant you may be more concentrated on what is going on in that area of your body than at other times. It may be happening when you are not pregnant and you may not notice since you are preoccupied with other things.
It is never bad to be worried or paranoid about a pregnancy, especially when you have not had success with two others. Although you normally wouldn't contact an OB about your pregnancy at this time, it doesn't hurt to ask if they could help you out and talk to them about your very real and legitimate fears. Some might suggest progesterone supplements if your levels never get high enough to carry a baby.
In these early stages, not much can be done if you do start to miscarry. The only other thing you can do is take it easy and try to do some relaxation techniques.
