I went thru the same thing with my hair. I totally killed it several years ago... I ended up coloring it one more time so it was as close to my natural color as I could get it, and I just let it grow. It's been YEARS now and my hair is finally long and healthy again. Took a lot of trims and patience, but, it was worth it. I randomly get the urge to dye it black again, but, then I remind myself of what it took to get it this long and healthy and squash that urge as fast as I can! lol