sunday vs. monday

what's with sunday and what's with monday?.. they are just few hours apart.. but why is there a big difference in my mood today?.. yesterday was so relaxing.. been chatting the whole day (with my mom even-thanks cuz!), calling friends.. such a light one.. especially after i had been to the church.. ooh, really felt so relieved!.. then suddenly, here comes monday.. the first day of the week when i usually wake up with so much energy.. but i can't describe the way i am feeling right now.. woke up on the wrong side of the bed?.. aarrrrrggghhhh!!!!!!... can someone take my brain off my head?..please.......