2 days ago (the day before my Hematology test) I woke up in the morning and felt like I hadn't slept in a week. I was basically bedridden the entire day. No nausea/vomiting, or fever. I just felt totally spent. So, I pretty much wasted the most important study day I had. I was told that this was probably a stress reaction, since I didn't have any systemic symptoms. The thing is, I certainly didn't feel overly stressed.
This happened to me once last year, too. Just an acute bout of fatigue that lasts for one day and is gone the next.
Anyone else experience/heard about this?