Which Time Of The Day Should Effexor For Anxiety Be Taken?

I take Effexor for anxiety. When is the best time to take it? I have been taking in @ night but it does not seem to work. The other issue is I had Bariatric Surgery in 2008. I (my Doctor)changed my Effexor to the regular release tablets rather than extended release. Would the surgery effect medications such as Effexor since my body does not process the same as people that did not have their digestive system changed? Thanks Jim