I've sort of lost track of how long I've been on, but it's around 6 or 7 weeks. All in all, I have to say I'm feeling better. Brain fog and OI are still pretty bad. But less fatigue during the day. Fewer muscle aches. Thing is, I'm not sure how much I can attribute to Valcyte because I also started Seroquel for sleep and so my sleep has been much better. I'm going to say it's a combination of the two. I finished the switch from Effexor back to Prozac and I think that's helping as well. I do feel very detatched and out of it on Prozac, but I was at a point where I was so depressed that maybe it was better to flip the switch and not feel anything (emotionally) for a while. Just going to keep on with the Valcye for at least 6 months and hope things continue to improve.