Why do I feel nauseous?

Had some blood work done 2 days ago for lower back discomfort, mild abdominal and pelvic pain. Period ended a few days ago and today I’ve felt somewhat nauseous. This is not normal for me to feel nauseous.

Honestly i don’t know if I would even describe it as nausea. I mean I’m getting this feeling in the pit of stomach that feels like nausea but the feeling is also combined with hunger. I ate awhile ago so🤷🏼‍♀️