How do I repair highlight damage? The strands are thinner and breaking off?

I had hair past my waist, now it is only to my waist and the strands are thinner! I am devastated! It took me so long to grow it this long and I only wanted a few highlights so it would look good for my husband who's returning from 15mos in Baghdad. Anyway, waaaaaaaaaay too much hair fell out. I was not told it would do this, and I should have made sure I had a consultation before I let the woman touch my hair. It turns out she was worried with green in my hair. I was trying to achieve a more natural blonde look. Anyway, parts are white blonde now and as I said, a lot came out, plus it seems my strands are thinner. I just want to be able to keep the long hair that I have without having to chop it up to the nape where the breakage is. Do hair repar treatments work?