I ave been nauseous since year i did pregnancy tests all (-) asked my doctor if yeast infection could cause it he said no what could cause this feeling?

Nausea: This symptom has many potential sources. You might be best to make a list of when you become nauseated and what its relationship is to other things (diet, position, time of day, people you don't like, etc.), and take this with you to see a doctor, along with your prior medical history if they have not seen you before. This may be gallbladder disease, or other. Good luck.