Hair breakage and extensions?

without any research I was desperate enough to trust a woman who used the hot fusion method to apply extensions to my hair. It looked great at first, but the hair was incredibly heavy and would dry out in a matter of days. I had to continue to go back to the salon.Anyway, I had them removed after a month of wear and was DEVASTATED by the results. My hair was twice as thin as it was before the application! I wore clip ins to disguise the damage. It is now over a year later and what has really seemed to help was a layered cut. However, the under layers are still very broken, short and somewhat sparse. I do not have any bald spots and the outer layer of my hair covers most of the damage. However, when I touch it and put it backthere are areas that are somewhat seethrough and thin. I was wondering if my hair has a chance to recover. I am taking ultranourishair, a gnc multivitamin for women and hairtopia.