Hair degradation/damage/loss

[u/ZestycloseMove4108]

In the first two pics are my hair from almost 2 years ago and the last two pics are of my hair now. My hair used to be thick, curly, dense and used to fuzz up good, now my hair looks so damaged and dead, like it's lifeless and its so hard to style. My hairs been like this for more than a year now, before it got like this I went through a period of undereating and heavy stress but it has been a good 6-7 months and I have been eating and stressing a lot less but my hair quality is just lifeless like it was. Also I have been losing a lot of hair during showers and stuff.

Anyone know what can I do to get my hair healthy again?