22 year old, losing hair rapidly. What should I do to regain my hair back?

Hair loss can be caused by any number of factors. Work with
a physician to determine if your condition is due to genetics, stress,
nutritional deficiencies, medical conditions or even side effects from any
prescription medications you may be taking.

It is best to start taking action when the hair loss is
still in its early stages. This can help prevent more severe manifestations
later.

For pattern baldness, a doctor may recommend taking Propecia
or Rogaine to help slow the rate of your hair loss.

If a hair transplant is done while you are still losing
significant amounts of hair, bald patches may develop behind the inserted
grafts.

Your doctor can also recommend the best time to have a
procedure, if this becomes an option. 

I'd recommend you see a dermatologist or hair restoration specialist to determine the cause of your hair loss. There are dozens and dozens of causes - and all have different treatment.Hair transplantation is only an option for certain types of hair loss (genetic hair loss, traction alopecia, scar camouflage, inactive scarring alopecia). It is never an option for individuals with rapid hair loss.