My Rational and Irrational Fears about B-School

A while back I asked you guys what I should blog about. Linda asked

are you having any uncertainties? what will you fear/dread/not like very much
about bschooL?

Ooooh yes. I have many fears and uncertainties about B-School. Some rational, some not.
First, while I am definitely certain that my matriculation at Wharton is the right decision for me, at times I realize the enormity of the decision to leave my job and spend lots of money for this degree and it hits me like a ton of bricks. Not only that, it's just going to be such a huge lifestyle change for me. I haven't been in school since 2001. I think I forgot how to do it. It feels a little like standing on the edge of a cliff getting ready to jump.
Speaking of money, I'm definitely worrying about my budget. With the additional temptations of living in the city - endless restaurants, drinking establishments, awesome shops, etc - downgrading from the professional lifestyle to a student lifestyle is going to be really hard. I'm worried about finding a balance between putting myself in massive debt and missing out on the social life of school and living in Philadelphia.
Another subject I have been discussing a lot with my husband is the pressure I feel to make the most of this opportunity. I am so excited about everything I'm going to learn and the networks I'm going to build. But two years feels terribly short. And actually, considering the recruiting schedule in the second year, I have far less than 2 years to figure out what my post graduation job will be. I have an idea of what I want to do, but I want to keep my options open as much as I can. But how to fit open options into the recruiting schedule?
Welcome Weekend was great, and I met so many great people that I can't wait to call my classmates. But one thing I've been thinking about is the size of Wharton's class. At 800 people, it's just too big to be able to know everyone. I know that I will make plenty of friends, but I wonder if the size of the class will make close friendships difficult to find? Also, as silly as it is, I am really hoping that the friends I've already made will be in my cohort. But I'm sure most of them won't be - the chances are too small. This makes me sad.
Finally, probably my biggest concern is how I'm going to fit in all the activities I want to do and still get decent grades. There are so many clubs and activities that I want to be involved in that I am overextending myself before I even start! Prioritization will be key, but I've never really been very good at that ...
I think those are the biggies. There's definitely not anything I'm dreading (well, maybe exams?)or thinking I won't like. I'm sure some dislikes will come up once I start, but for the most part I'm really looking forward to getting started. Pretty much can't wait, actually!