My Wednesdays in second semester of last year had
13 hours of class, with about 7 or 8 of it being lectures. I think I had 4 lectures back to back and I survived fine. When I get around to turning on my desktop, I will post a pic of my schedule and then I am sure you will feel fine
Also all night classes are 3 hour blocks of lecture, and although it may be hard to stay awake, if the profs are good then you will not have a problem