Hi,as you are 17 year old and loosing hair due to stress,I would not advice you to go for any hair regrowth treatment for now.
What you can do is get your iron level,Vit.
B12,Vit. D test done.
Take multivitamin containing biotin,
calcium pantothenate, zinc,trace elements,vit.B12,vit.D etc.
If it is because of stress it will regrow back,and if there is any deficiency then when the cause will be cured your hair will regrow back.
Next Steps
But for proper diagnosis and treatment you should consult cosmetologist or dermatologist.
Health Tips
Try to calm down yourself,enjoy your life .
Eat healthy food rich in protein and antioxidant rich fruits.
6-7glasses of water daily.
Use mild shampoo according to your hair type.