Actually, that doesn't sounds like that bad of a schedule... 5 nites a week, 10 credits for the semester? At least you'll have time after class to hit the library for a few hours each night to do some reading.
Assuming that I'm correct on the credit count, figure 2-3 hours of study for each hour of class means you'll need to put in 20-30 hours of study-time each week outside of class. Taking 2 hours each evening in the library after class(M-F) gets you 10 hours during the week if you only stay until 9:30. That means you only have to put in 10-20 hours each weekend.
What's a day in the life look like? Well, my experience while working FT 8-5 had me in class 4 nights a week (generally between 6:30 and 10). Reading during lunch gave me 5 hours of study time each week, opening and closing the library on both Sat and Sunday gave me another 22 hours, and then usually one weeknight class would either start late or finish early and give me another 2 hours to read. A day in the life of a PT law student that works FT means not having time for anything outside of work/class/study/sleep... and the sleep part tends to get crunched a bit. It also means that some of the people you're competing against for grades may (will) have a time advantage because they work less hours (or don't work at all). That's where you're really going to see the toughest competition.
The one bright spot is that as time goes by, you get faster at doing the reading, you learn to take shortcuts regarding briefing, and you get better at balancing your time. The work doesn't get any easier, but because you've developed the tools to compensate, the burden isn't as oppressive.