I'm almost 2 weeks into the program. The short story is that the program and demand are more intensive than I have thought. I have 18 hours of classroom time per week. I estimate that for each hour of classroom time, I need to put in at least 3 hours of work... doing the readings, working on the problem sets, preparing the discussions etc. That's makes a total of 72 hours of work per week.
Thus far, the work has been very challenging, especially for the microeconomics and econometrics classes that I'm in. The lack of rigorous mathematically background is making it really tough for me in these courses... (P.S. I'm not even doing a econs phd. Just that my program requires me to take these graduate econs courses.)
Sweat. Persevere. Just do it.