Hair loss problem. Is it right or not?

Hii...I am 17 yrs old and i am facing some hair loss and dandruff problem from a lot of time before but from three to four months the rate of hairloss has become very muchh severe... everyday i am losing so many hairs day by day due to which my hair density has become half of what it was earlier and because of this I'm very much depressed ... So that's why I visited a dermatologist yesterday and tell her about my this problem and she prescribed me to use hair agen minoxidil 5 % solution , a pill in which biotin vitamin supplements were used and kenozote shampoo for 3 months and to wait for better results ... so I want to ask you that are all these medications are right for me as I am just 17 yrs old or not and I also have one question that I have heard from internet that if I start using minoxidil solution then I have to use it for my lifetime and if I stop using it after 3 months then all the hair which grown will shed of is it right or not ? Pls help me doctor ..