I went through something similar a few months ago, but I was more sick from the meds I was put on than anything else, and it took me a while to figure out what it was... I'm still shocked that the psychiatrist I was seeing didn't see or care that the reason I was so sick was because of the meds she put me on. I was constantly tired no matter how much I slept, had headaches, vertigo, nausea, and became really depressed. I had to quit my job because I was so sick. And about a week after I discontinued the meds she'd prescribed me out of frustration, I was completely fine. If I hadn't tried that, I probably would have been sick for a lot longer with no idea what was wrong.