I've been feeling nauseous for a week. can't eat, can't sleep, my body feels so tired i don't feel tense i feel so light i can't get up an when i do i start to feel very nauseous?

Check for pregnancy: There are multiple of causes of nausea, but it is a common symptom of early pregnancy. Often is mild, but for some women it can be quite severe and causes symptoms you are experiencing (hyperemesis gravidarum). So, i would do a hpt. Consult doc for an eval as this is not normal if you have been in general good health. Good luck.