I know it is too early to worry about it as I am only 5w1d today but I am hardly ever sick (yet). With my three children I had really bad m/s from about 6 weeks and I can not remember (and my diaries say nothing about) the week before. The two m/c I had were missed m/c and I never had any morning sickness. So this is my personal most important sign.
Are you sick yet?
Did you have a pregnancy that was healthy where you had no m/s at all (maybe even after one where you were sick 24/7)?
Please reassure me!