I have been nauseated for a week straight.... Neg preg test... Appetite suppressed... Maybe stress? Don't know what to think...

Could be stress. Reduce caffeine intake, may drink Cocconut water. Relax and take deep breathing exercise. Chew dry ginger root and clove. It helps Nausea. Do not eat solid food for couple od days. .If not better , get help from your MD.
Nausea. Nausea is a symptom of over 1000 different medical conditions. It is absolutely not in any way a symptom of pregnancy before a missed period. Please go see your physician for an evaluation.