Just to latch onto the undiagnosed ADHD bit: Having it diagnosed formally may help, getting medicated for it might help, but... it's not a panacea. My girlfriend (diagnosed mid-30's and on slow release medication) describes it as a mood stabilizer moreso than a magic cure. Doesn't fix procrastination.

I tried it once (trying the medication is part of the diagnosis), I found myself switching tasks with Intent and being really focused on one thing at a time, vs my usual mode of "multitasking".