Billy, you can do it all! You probably are doing a lot of it right now! You definitely are getting exercise if you are working, chasing kids around and taking care of your home. Just pace yourself when cleaning and, if your children are old enough, start passing out chores. A six year old can dust and an eight- nine year old can run the vacuum, etc. My kids started doing their own laundry when I found their clean clothes, still folded, tossed back in the dirty clothes basket because they were too lazy to put them away. SURPRISE!!! They certainly didn't think that would happen! 
It was good training for them. But, if you are working, they need to pitch in, too. You are a family and everyone needs to participate...not just you.
You can watch the foods that you eat, stay away from a lot of carbs, and eat foods that are more alkaline...fruits and veggies. You can get lists of food by googling it. You also can drink plenty of water throughout the day.
Keeping a positive outlook can be done no matter what you are doing and it really does help. There is a link about maintaining a positive attitude in Fibro 101. That would help you.
You can put yourself on a sleep schedule, too. Once the kids are in bed, you head there too. The rest definitely is necessary for you if you are a single mom who is working, too. This is important. If you go to bed and get up at the same time every day, it really does help a lot.
You do have a lot on your plate but using some of these techniques will help make your life a little easier and you will get some relief from your pain. Just remember to pace yourself whenever possible. You honestly don't have to be Superwoman...even though you feel like it at times. Pick your battles and get help from your family. It actually can bring you all even closer together.
Sherrine