I am a 19 year old female and I have been feeling very nauseous on and off since last Thursday morning (so today, Friday, is day eight). It is especially bad in the morning, once I've woken up a little bit, and was exclusively in the morning until two days ago. No vomiting yet, and no diarrhea until this morning, which had a lot of yellow in it.

The nausea comes and goes with no discernible cause (I felt sick Thursday morning then pretty much fine til Tuesday, since then it's been every morning). I went to my campus health services and the nurse thinks it is a mild case of the stomach flu, lessened by the flu shot I got in December (I saw her before the diarrhea). Is this the most likely case?

Also, I used to experience anxiety attacks that made me feel nauseous, but it's been a very long time since that happened, and it's never lasted this long/been this bad except for the first one I ever had. I was wondering if it were perhaps psychological, as when I feel terrible right after I wake up, walking around seems to help a little. Am I just crazy?

Another thing that I don't know if with all this information it would've even come up, but, obviously searching "morning nausea" online yields a very narrow list of possibilities. It is quite impossible that I would be pregnant.

Sorry for rambling, the nausea is becoming very trying and I'm feeling exhausted. Any help you can offer would be appreciated!