Nauseated ALL the time?

For the last week or so, I've been sick to my stomach constantly, on the verge of puking. I know I'm not pregnant. I eat alright and exercise daily so I'm not sure how to get rid of this. I don't really want to go to the doctor because with such a broad symptom of nausea, they can't really do much.  Any suggestions? I've been eating tums like candy and it's not working out well!