Sounds like ADD to me, just because it's all so familiar! I've got it bad. Although I made it to age 40 without being diagnosed. Only came up then because my son was tested and diagnosed in high school. When I read the psychologist's report, I said - "hey! That sounds a lot like me!" You're probably pretty intelligent, the ADD/high IQ combo happens a lot, and explains how we make it as far as we do in life without knowing what's going on.
You're right that treatment - whether meds, supplements, dietary - are only part of the solution. You need coping skills built into your life, BIG TIME. Here's a laundry list of mine. And read this book for some ideas.
Amazon.com: Driven To Distraction : Recognizing and Coping with Attention Deficit Disorder from Childhood Through Adulthood: Books: Edward M. Hallowell,John J. Ratey
1. A portable clip-on timer. So when you're cooking/baking anything you can put the timer on your body. That way when you wander outside for "just a minute" (that turns into lots of minutes because you start playing with the dogs, then notice the garden needs weeding, the roses need watering...) you'll get notification to remember about the food cooking and won't walk in to a grease fire on top of your stove. (True story by the way).
2. Alarms for lots of things. Use your cell-phone alarms, kitchen timers, whatever works to prompt you to stop whatever you're doing and do what you're supposed to do next.
3. Write everything down. EVERYTHING. I use a daytimer that I carry with me, a big calendar over my desk, and I have a dry-erase board hanging in my kitchen. The dry-erase board is great for keeping a running grocery list and short-term notes to myself.
4. Speaking of grocery lists - years ago I created a spread sheet of anything and everything I might ever possibly want to buy at the grocery store. Even making lists like I do, I'd inevitably forget something on shopping day. It's not such a big deal now that it's just me, but when I was raising a family, I'd print my list out and check off everything I needed.
5. Minimize chaos and distractions in your personal space as much as possible. There's enough wild activity going on in your head! You don't need it in your environment, too.
6. Establish a habit of meditating. Yeah, I know. Sounds impossible, right? But once the habit was established, I have found meditation to be a valuable tool in calming and focusing my brain.
7. Routine, routine, routine! You're less likely to *space* regular, everyday stuff if you establish and stick to a daily routine. Then when special events or activities outside of the norm occur, use your lists to remind you where you're supposed to be, doing what, when.
8. DAILY physical activity - OUTSIDE. Walking, running, biking...whatever. Keeps your head clear. (There's studies showing the benefits of engaging in physical activity outdoors on kids with ADD).
9. Purchase all small appliances with an automatic shut-off feature.
I'm sure there's other things I do but I'm drawing a blank at the moment (ha!). One other note about stimulant abuse - I worked for a clinical psychologist for several years and he often made the statement that people who make it to adulthood with undiagnosed and untreated ADD, WILL self-medicate. Drugs, alcohol, copious amounts of caffeine - whatever they can get their hands on that will help them feel "right". That may be what's going on with your family. And as far as meds are concerned, if you've only tried the one medication, I encourage you to work with your physician and give some others a shot. There's lots of meds with different effects on different people. There may be something else that works really well for you.