Coming off the heels of 900km of crit racing you might be a bit cooked. That's a lot of intensity, and equivalent to two shorter stage races. Without getting deeper into your schedule and metrics it's a bit of shooting in the dark, but a week of easy probably won't be enough to recharge, especially if you're jumping right back into things.
For me I usually see my performance getting erratic right before the wheels come off. One day you'll feel great, then the next you can't pedal. Mentally I get fried too. Everyone's different, but that's a lot of hard racing in a short period...