Can hair lost due to stress grow back?

Can hair lost due to stress grow back again ? I am doing night shift job..hence dont sleep at night...last year (January '17) my sleep was very poor...I used to sleep only for hardly for 4 hours...my digestion was affected due to improper eating timings...had zero sun exposure (my vitamin D was below normal)...and suddenly (March'17) my hair started thinning and then started falling...my body became weak...thyroid level increased upto 6...my nails of my toes started chipping off when it grew.. I started taking biotin and vitamin D tablets and the chipping off of nails stopped...my vitamin D level also became normal however my hair was still falling...I changed my shampoo and started using Anaphase and had 2 sessions of PRP(Jan'18 May'18)...so my hair has stopped falling but is still not as strong as it used to be...my main concern is I lost a lot of hair and would want to regrow and strengthen it...Is it possible to regrow my hair back?? I have attached hairline pic of 2017 and 2018