My Hair :(

My hair has been falling out A LOT, and so I decided to let it grow out back to my natural color and leave it be. My hair will probably all fall out and regrow, I'm assuming my hair became overprocessed as I have very delicate hair. BUT I'm super sad because I love the color I have now and I don't want it to go, I've had it for three years! :( anyway, does anyone have any tips for hair growth? I've never tried castor oil, does it work well?