I feel your pain. I can hardly focus at work right now.

In 3 weeks, I'm going on vacation to Europe for 10 days with a friend and I'm starting to worry that my fatigue (that keeps coming and going) will ruin my vacation.

I wish I had some good advice to give you but unfortunately, I don't. All I can say is hang in there! I did recover from severe depression several years back. Unfortunately, difficult circumstances have caused me to relapse.