I'm sorry I can't really empathize with the ADD since I've never been diagnosed with it. But I would like to encourage you to see if you can use it to your advantage. Even though I can focus on a project, specific parts can be very tedious and focusing too long on something can get stressful. If you can instead find a way to work on one small chunk at a time (or shifting gears between multiple small chunks you're currently working on) you might be able to create something cool in time.
Best of luck, and I hope you find the method that works best for you to get your where you want to be!