Suggest Treatment To Increase The Thickness Of Hair

Hi, M simi, my height is 5.2" n weight is 50kg, i had beautiful hairs till ma school days, then when i was separated from ma friends i was under depression and was down, i used to had problem of stomach upset almost for an year. i consult doctor, at that time i was almost bald bcoz of shedding hairs, den i recover n till now i didnt get ma hairs back
they are very thin n week, what to do?? i have proper deit but its not workig