The sicker you feel...?

Just making conversation here... I'm not particularly worried. But I've heard that nausea and vomiting are a sign of a healthy pregnancy. I've even read in some places that the sicker you feel, the healthier the pregnancy.
I'm just wondering because I don't feel all that sick. Mainly, my tummy just feels tender and delicate. I'm not worrying too much over it, I'm just curious what others have heard about this. Old wives' tale, or actual science?