On the weekends, I get up 3 to 4 hours later than I usually do on the weekdays; however, I've noticed that its harder to wake up. This makes sense to me since without the medication, I feel drowsy. My question though relates to after I take it. When I do get up and take it, even after a few hours, I still feel just as groggy and sedated. On the weekdays, this doesn't happen, so I was wondering if anyone else experiences extreme tiredness when they take Viibryd at a later time?