Nauseous and Vomiting

Hi you alls, A FTM here. I’m at my 20/21 weeks of being preggy and I suddenly got my dreadful and horrendous nausea and vomiting back after going through the phase in first trimester. Any mumsie facing the same problem? What’s happening, why does it appeared back? It makes me feel so demotivating and kinda dehydrated. #firstbaby #firstmom