Eh, some of us still kena the nausea at week 19 lah, memang it doesn't always go away by second trimester, my friend pun rasakan jugak, tapi usually it's less intense than first trimester. Lepas you makan apa yang heavy ke, or maybe iron supplements, boleh jadi trigger juga, so try makan smaller meals and munch on plain biscuits throughout the day. But sebab you're feeling like throwing up macam first trimester lagi, better check with your doctor to make sure everything's okay la, sometimes it's normal, sometimes ada other reasons they should know about.