Don't be worried. As you will hear time and time again, every pregnancy is VASTLY different. Sometimes women are sick from week 1 (well, technically 3, I guess ;) ), and some women don't feel a thing until they're huge (and then the symptoms are pretty obvious).
It is true--miscarriages are unfortunately very common, but symptoms are NOT a reliable way to know if things are going well with your pregnancy. They will come and go and change and taper off and then hit you full force.... or never show up at all. All you can do is live a healthy lifestyle and get proper prenatal care and hope for the best. Chances are, things will go great for you and your baby!!