hi rab,

Two things. Like most areas of studies you get out what you put in. That being said, a large part of what architects do is communicate ideas. Mostly we do this through drawings and images and through speaking. If you are not confident in drawing and speaking ( and feel it is not something you can learn/master) then architecture is probably not the best field for you.
The market is bad, which means it is very competitive. The few jobs available go to people who can communicate their skills very well. So again, drawing and imagery matters during the economy.
The lack of an arch background is fine, the goal of most march1 programs is to teach you the skills and ideas behind being an architect.
Workload is overwhelming but for me its a good thing. I like the push and stress. some don't.
Lack of sleep is not a requirement...but I can't think of any descent student from my under grad, or current grad school who slept alot...most are working all the time, sleeping in spurts. You could be an exception, and im sure there others out there who have done school and sleep.
I was pretty well rounded in Undergrad. Hope this helps.

1) It should be doable as long as you manage your time properly, although don't be surprised to find a bit of a culture shock compared to business school. Aside from maybe a few hours per week of work-study, I'd suggest avoid trying to hold down a part-time job while you're in school, at least until you have a better idea of what you can do.

2) Pace yourself and make time for sleep, and this shouldn't be a problem. One of two all-nighters at the end of a major project won't be unusual, but if you're consistently pulling all-nighters, then something is wrong.

3, 5 and 6) Don't worry about it. Nobody expects you to be good at that stuff when you start an M.Arch. program, as long as you're good when you finish.

4) Since you won't be finishing your degree for at least a couple more years, the job market will hopefully have improved a lot by then. This is actually the perfect time to be starting grad school.

i'm in almost the same situation as you.

1) from your experience in the professional world, you've probably become a harder worker, and more efficient, and definitely more mature, so this adjustment should be easy.
2) again, efficiency is a big thing here, and I think your efficiency will increase over time. I'm expecting the first semester to be very time consuming, but better after that. and a couple all-nighters at the end of projects is assumed, but shouldn't be a big deal. and i'm married, so trust me, this is a big deal overall.
3) just about anyone can learn to draw. some might be particularly adept and inspired, but drawing skills come from a basic set of principles that are widely known and taught. your school will likely baptize you by fire in this respect, and you will probably surprise yourself.
4) see #4 above. people are fleeing the working world for grad school for good reason. if the USA isn't in a better financial place in 4 years, it probably won't matter what field or industry you're in. maybe a wilderness survival course would be a better option in that case.
5) many people in academia in the industry prefer MArchs with no BArch--there's a lot to be said for a well-rounded education, and you're biz admin skills seem an obvious advantage post-grad.
6) not sure what to say about this one, other than suck it up and get better at it. when presenting in class, everyone is nervous, and everyone understands. the key is to really develop your ideas deeply prior to presenting. a cornell prof said to me once that it is possible to show up to a crit with underwhelming physical work and still succeed conceptually and verbally.

the most important question for me in this situation overall was: How will you feel in a year if you don't go? And the answer was inevitably: probably stagnant and regretful. but that's my case.

Congratulations!

1)been out of school for 7 years. i'm worried that the workload will be overwhelming.
There will be a lot of work, no doubt, but since you've been in the working world for a while, you are probably pretty good at managing your time.

2)i dont work well having had less than 6 hours of sleep a night.
This goes back to #1, if you manage your time well, you shouldn't have to pull all nighters. People spend a lot of time socializing in studio, which is great, but some people don't budget their time well and have to cram to finish a project for a deadline.

3)im not particularly adept at drawing(although i am creative in other ways--abstract painting and music)
Do people still draw in architecture school?

4)the current market for architects.
It sucks, no doubt, but you'll be graduating in 2012? The market will probably be better by then. Though, keep in mind that the architecture business is cyclical. So, every 10 years or so, expect a lot of slowdowns and layoffs.

5)have no arch background
In my class, about a third to half the students had other backgrounds. You won't be alone.

6)im a bad public speaker(nervous)
I hate public speaking too, but developing the ability to explain a complicated (and later, expensive) project is a very important skill. Fortunately, you'll get plenty of practice :)