Finally, after 15 days of high functioning (above 75%, with only mild flu-like symptoms), I came crashing back down today. But this time, instead of bemoaning the crash, I just feel thankful for an unprecedented run of good days. I knew it had to end some time, so I tried to enjoy every minute of it while it lasted. I haven't strung together 15 good days since I became ill in June, and one of those days was my best ever (based on my personal rating scale). I'm not sure if the Famvir or the methylation protocol had anything to do with it, but it's certainly possible.
As for what caused the crash, I have two theories. 1) I ran a couple of errands yesterday and allowed myself to become stressed out. I ran late for two appointments, and found myself speeding around and yelling at other drivers. It felt so good to be part of the world again, I got carried away. While I wouldn't normally think this could cause me to crash, I've been warned by so many veteran ME/CSFers that days like this can cause a crash, that I tend to defer to their expertise. I simply have to learn to take it easy when I'm feeling good, or I'll be doomed to repeat this cycle.
2) The other possibility is that the crash is a reaction to taking low dose naltrexone (LDN). I began taking it last night, starting with a very low dose of 1.1 mg. But, the commonly reported side effect of starting LDN is insomnia, not fatigue, so I'm less inclined to give credence to this theory.
Finally, the good news! I've been on the waiting list for my first choice ME/CFS specialist doctor, but his schedule is so impacted, he couldn't see me until late August! I just learned a few minutes ago, by a stroke of good fortune, my appointment has been moved up to April 27th--four months earlier than expected! I'd do a little dance if I had the energy. If you're reading this, thank you to the person who helped move my appointment -- you know who you are!