I swear I had more money earned this morning and now it's gone down during the day. Am I hallucinating or have you seen this happen?
It's possible -- if Google decided some of the clicks were invalid. Were you looking at actual earnings or eCPM? eCPM can go up and down during the day, even though your earnings go up as you get clicks.
You are not hallucinating. It's rare, but it happens. They sometimes they correct your earnings if they decide some clicks are invalid.
If you are involved in activities such as invalid clicking on your ads , then the earnings can go either way