not firing on all pistons

Went for ride b4 work this morning. Didn't feel all there. Several potential reasons.

-coming off 2 days rest, always takes me day or two to get legs back
-had good nights sleep with Ambien, possibly feeling lag of too much sleep
-Had bagel and cereal, no protein for breakfast. I think I'm mildly hypoglycemic so i need some protein to anchor it all down
-possibly still not recovered from that 4hr ride few days ago

whatever, just cut it short and went home, got all year to flog myself. Plus got lots on my mind with work, so its hard to just push that aside when out on a ride.