the first week?

How was your first week? Do you feel like you have mounds of energy? Nope? That is normal, don't expect change overnight. If you got your three days of twenty minutes then, you did awesome. Seriously! This is the part where I should tell you not to get on the scale, but, since I'm a 'scale junkie' that would be hypocritical of me. I would just suggest that you stay away from it if you can. You may have gained a pound - but it is OK. Weight loss is a 'process' not an instant gratification thing.
I heard people mention 'workout' buddies. You know, someone to motivate you to exercise. If you are a self-motivator, you don't need one. If you need someone to tell you to get up off your ass, then get a motivator that will tell you that. Don't ask a sweet neighbor to be your workout buddy. This is serious business. I would even go so far as to recommend you pick a workout buddy that already has a habit of working out. They will keep you in line. If you can't find one amongst your friends, then I would suggest paying a personal trainer to exercise with you three days a week until you can motivate yourself. But, be ready, they'll make you work. Of course, if you can afford this option, then, use that personal trainer to the extent that you can and have them start you on a workout plan.
The other thing 'buddies' can be good for, is sharing exercise tapes/dvd's. In two weeks, we'll be changing up the walking for some other types of exercise and in home videos are GREAT options. If you can share in the cost - that is even better! So, look out for sales on the video's or check and see what blockbuster/netflix memberships have available in the exercise videos. If you can get a 'turbo jam' video, I would highly recommmend it. it's dancing and fun and the instructor "Chalene' is encouraging and funny without being 'over-the-top.' I also like Kathy Smith workouts - but, I tend to like 'goofy-funny' and she really knows her stuff. IF you like 'cutsie' then Denise Austin will work for you, she also knows her stuff, I just find her really annoying.
Next week try to squeeze in one more day of twenty minutes of walking.
As far as food goes, you may have noticed an increase in appetite. Sometimes, your body needs water and it feels like 'hungry.' if you get the munchies in between snack and meal, then down a glass of water and see if that holds you over.
Two tricks -- I'm a major chocoholic. If that is you, here is something that got me through the early days. I bought a bag of miniature chocolates. I would put one in my lunch every day. Or, I would buy those nestle semisweet choc chips and just put a small handfull in a baggie and take a few every now and then when I felt like I was needing chocolate.
Second trick, if you find you are needing to eat out. You already know what is healthy to pick, but you feel you are being 'deprived' of some fabulous french fries, go ahead and order them. As soon as you get the meal, take half of the french fries and ask the waitress/waiter to take them away from the table.If you ordered a sandwich, then ask for a to-go container and put half the sandwich in the container and put it no the seat next to your purse. Out of sight, out of mind. If you can split the meal with someone, that is even better!!!!
Okay, get up and get moving -- happy exercising and enjoy your journey!!!