Growing Long Hair

I realize that this question may not be able to be answered, but was curious as to anyone who perhaps may be in my position.

When I was a child, my hair was always very long -- past my waist and almost to my hips. I've always had fine hair, but quite a bit of it and have not worn it long since I was 12.

I have only been able to grow my hair to about 2 inches past my shoulders, after that point, it just breaks off and looks frayed, so it always ends up being cut and always being the same length.

I've recently started taking Hair Formula 37 Vitamins (I also take a separate MSM supplement) and re-vamped my diet to include lean protein with every meal, lots of colorful vegetables and several fruits per day and lots of water, in addition to the good fats, i.e. flax, borage, olive, etc. I don't smoke or drink alcohol either. I'm wanting to grow my hair to at least halfway if not longer down my back and am unsure if this is even possible, or if anyone in the same position as I'm in has been able to accomplish it. I'm wondering if coloring my hair with permanent hair color is affecting my ability to grow my hair long (I use Loreal, and only on the roots -- never color over color).

I do blow dry my hair every day, in addition to curling it (if I didn't, my hair would look really frizzy and thin) and using hairspray in a small amount.

I just want a change, and would like any input from those of you who have accomplished this.

Thanks for any feedback you can give! :)