Food poisoning or?

So since last Friday I've been really feeling sick I ate a pizza from Little Caesars and then maybe like an hour or so I started feeling really sick and I was thinking maybe I ate too much or it was too greasy and then the next day I still felt like s*** I felt really nauseous and so throughout the whole weekend and up to this week I've been feeling nauseous all the time whenever I eat I feel nauseous whenever I don't I still feel nauseous but when I drink water I feel fine I'm a little bit worried if it's pregnancy symptoms or food poisoning . I haven't been throwing up and I don't have diarrhea I just been feeling really nauseous any help ladies?