Hi trinity:
A couple of questions: Have you just started or stopped a new drug? Have the symptoms gotten worse today?
I'm personally not surprised that you would feel exhausted after a vacation. I always do. What you describe sounds like exhaustion and anxiety to me, even the feverishness. If the symptoms let up in a day or two, it's not serotonin syndrome. But if they don't, just like anytime you have a fever that doesn't let up -- call the doc. I found a good article describing the syndrome -- here's a link.
www.nlm.nih.gov/medlineplus/ency/article/007272.htmHope this is helpful,
serafena