I am terrified of vomiting. I will lie motionless on a couch for hours rather than vomit to get it over with. For me, morning sickness has never involved vomiting because I fight it and will not let myself. So it's just the constant feeling of being full, dry heaving, burpy, gurgly, and like my body is going to explode. It is a miserable feeling.
In my experience, doctors are very responsive to nausea alone--if it goes unchecked, it can lead to weight loss and malnutrition due to the very strong food aversions. With DD I was put on Zofran, but I will never do that again and I think there are even some warnings out about it now.
What works best for me with this pregnancy is a few bits of chocolate throughout the day for small energy boosts, preggy pop drops, sipping very spicy ginger beer (non-alcoholic, of course), and drinking fizzy water. The ginger ale and fizzy water cause burping, which helps me a lot, and ginger is a natural stomach settler despite how spicy it is. Another thing that really counters the fatigue and nausea both is a walk out in the cold--I don't know how it works, but it does