Hi Lisa, I'm about the same height and weight you are, so I feel where you are coming from! I also have been this overweight for a while now, and I remember being in college and being the heaviest girl in the room...it sucks! It does all kinds of messed up things to your self esteem and I always felt yucky and invisible! But I'm so glad you're here and making a start. This is a great place, I just started 2 weeks ago and being here every day or so has kept me on track.
I do a combo of a low carb and low cal diet, I use the website
www.fitday.com to track the foods I eat, and I excercise in some way everyday.
Take it one meal at a time, don't worry about getting it perfect right away, and give yourself lots of encouragement...you're here and you're going to do great!
By the way, I just had my son, and I'm so impressed that you have 5 kids and don't weight more than you do! I gained quite a bit with Leo, and it seemed like the hardest thing not to snack when he was stressing me out!
PM me if you'd like to talk more!
Hope