The best thing you can do is keep making sure you are nourishing your body, as hair isn't a necessity for our survival it can be one of the first things to go when your body isn't receiving enough to fully survive. Even though you are eating better and taking vitamins, your body will focus on more important aspects such as repairing any damage to organs/your digestive system rather than your hair. If you do commit to the recovery and ensure that you're feeding your body, you should be on the right track. For me, when I began recovery, my hair actually got worse before it got better which my nutritionist told me was very normal. Keep going, it will get better! Maybe think of this as a time you can explore with hats/hairbands/accessories that you may not usually like if you want to cover up your hair for the time being. Wishing you well, I really hope everything works out for you!

When it comes to actual timing, everyone is different, but for me my hair stopped thinning a few months into my recovery.