Seriously confused.

I'm not the greatest at keeping track of time (minutes and hours or weeks and months)- If I am writing a check I will for sure stare blankly at the date line until someone offers me the month for starters. And I don't have kids in school so I don't have a great gauge of seasons. Now, since we just went from endless summer to Autumn in July to a September heatwave I am really messed up - the Christmas decor popping up in the stores doesn't help either. But I really thought I had a handle on what day comes after Sunday. Today's Monday right? How come everytime I go to MSN.com it says Tuesday September 23 at the top. Did I sleep right through Monday? No wonder I got up so early today after being up so late (at least what I thought was) last night.