Its the hormones na, very normal. My mother gave me a little lemon and ginger which calmed my tummy. But if you cant keep any food or water down, please tell your doctor, that needs attention.
My gynac said its mainly the surge of pregnancy hormones, especially hcg, that triggers it. Your sense of smell also goes into overdrive which makes it worse. It usually settles by the second trimester for most.
Hormonal changes, plain and simple. The body is adjusting to the pregnancy. Empty stomach makes it worse so keep nibbling something light through the day, dont stay hungry.
Its the hormones rising fast in early weeks. I lived on dry biscuits and ginger water, eating small bits often helped me more than big meals. Hang in there, it does pass.