Nausea & loss of appetite

My period was on from January 21- January 25. According to glow this is my fertility week. But I’ve been feeling extremely nauseous and i have to force myself to eat bc if i leave it to my appetite I would starve thats how bad it is. I can’t eat without gagging 🤦🏽‍♀️. I have NO clue whats the reason behind this. My boyfriend and I have been TTC but its to early so i guess thats out the list of options. Can you help me out and comment some reasons this could be happening. Its been going on for days. I don’t exactly know which group to post this in so excuse me if it’s wrong.