Hi J.,
Sounds like you're on the right track.
With 8 kids I'm sure you're VERY busy! And with all that business you may not REALLY be paying attention to what you are eating. I have found that I do BEST when I actually write down everything that goes into my mouth.
A great website is caloriecounter.com It can help you track your caloric intake, what you should be eating, and help you get on the right track.
It's not just about moving more. It's also what you're eating. BALANCE BALANCE BALANCE! I've found most 'diets' cater to one type of individual (and for every diet that is different). Some people will loose tons of weight by cutting out carbs, some will loose by cutting out other things. BALANCE is key. We all need carbs, and fats, and proteins, and fruits and veggies.
Adopting a healthy diet... LEAN proteins, lots of fruits and veggies, moving more and getting enough rest are the keys to success. Now, don't get me wrong. It isn't a magic formula and by no means am I perfect! ha ha ! I have some pounds that need to go! But, when I really get serious about it... following this 'formula' works wonders.
When you hit a wall, then your body has adjusted to your 'new' routine... and you have to change it up. You say you walk 3 miles each night. That's great! But, what about biking 6? Your body becomes used to the new thing then you have to engage new muscles.
Also, by really taking a look at what you're eating, I think you'll be surprised. I know I always am! You have to write down EVERYTHING that goes into your mouth whether it is food or drink. It ALL has calories.
Journal it for a few days and then go back and look at it. See what is going on. I know when I am really busy I don't always THINK about what I am eating and then it adds up.
Also, watch your portion control. Drink LOTS of water. HYDRATE HYDRATE HYDRATE! Rule of thumb.... 2 liters per day. It will not only keep you hydrated, but help you feel full at meal times so you don't over eat and will help flush out your system. Your urine should be or be near colorless.
Good luck!