The symptoms & case history mentioned in your post suggest that you might be having Androgenetic alopecia.
Also known as Male pattern baldness
, it usually follows a pattern of receding hairline & is related to genetic makeup and male sex hormones.
preparation to be applied directly to the scalp to stimulate the hair follicles.
preparations that interferes with the production of male hormone linked to baldness.
But these medications have to be used regularly under the guidance of a Dermatologist...as hair loss tends to return on stoppage of these medications.
Those cases which do not respond to medical therapy, are managed by hair transplantation
So...it will be better to consult a Dermatologist
& start treatment.
There is no need to worry, your hairs will grow again.
Wishing you a Good Health.
Let me know if I need to clarify further.
Thanks & take care.