Is this IBS?

Sarah • Student. Trying to figure out life.
So I'm a big girl. I like to eat. When I eat too much, my body gets rid of the excess via (cough) faster digestion.
However, for about the past month to six weeks, I seem to get sick with everything I eat. I already ruled out spicy food. But even plain and innocent things will make me sick. Sometimes I get sick ten minutes after I eat something, other times it's multiple hours later. The attacks vary in intensity, too.
In the next month or so I hope to talk to my PCP about it, but I'm a busy student and she's out of town. Advice in the meantime?