16 wks. Random morning sickness and hungry

So I've had morning sickness since 5 wks really bad. It's been getting a lot better in the last few days but by 4 pm I feel stuffed and get full off the smallest amount of food or if I eat it's a 50/50 chance I'll throw it up. I don't remember experiencing this with my first and by 15 wks with him I was better. The best way to explain it is that my appetite is back normal but my body isn't. Like I want to eat this 3rd slice of pizza but my body is saying no you'll regret it. And my food just sits there in my stomach for hours! Ugh! I just wanna eat this 3rd slice of pizza.