Is this a feeling?

Hi! I’m working on identifying and labeling my feelings. But yesterday I realized that something might be a feeling that I always assumed was hunger.

I was working yesterday and had this nauseous, empty feeling in my stomach. So I ate my salad, beans, pumpkin. But the feeling was there an hour later. So I ate something else. After continuing in this fashion for the whole day, it dawned on me that maybe this wasn’t hunger but either 1) I ‘m nauseous for a medical reason, or 2) this is a feeling. I woke up this morning and had my coffee and the nauseous/empty feeling returned. My feelings tend to be anxiety, overwhelm and stress which I’ve been working on with models, etc. How do I know if this is a feeling or not? I could not identify an exact thought that could have triggered a feeling and was actually quite pleased with myself yesterday because I was producing results, etc.
Any suggestions you have would be much appreciated.
Thank you!