When 13 hours seems normal...
There is a point in each day where I count the hours I've been working. I am a theatre major, so there is no shortage of long days. Tech week alone can consume between 10 and 14 hours a day.
I have my classes, and work, and rehearsals, and homework, all time-consuming endeavors, and it is hard to roll out of bed every morning and face a day that long. But in the end, what helps me get my feet to the floor is that it is worth it. Every hour I spend working does pay off, and whenever a show goes up on it's feet, I feel entirely justified.
It's worth it... if you're tough enough.