Had anybody felt this way before?

Recently I've been feeling sick. Like not all the time. Only when I get food and I sit down to start eating and before I even take a bite I get a stomach ache almost nauseous. I still eat to see if maybe I'm just very hungry but I still feel sick. I don't think I'm pregnant because according to glow I ovulated this week. I've also been really tired and having headaches and a little bit of dizziness. I've started taking vitex a few weeks ago. Could it be that. If it continues, I'll go to the doctors because I'm afraid I'm not eating enough and that could be the reason why I'm tired all the time.