The most common cause go hair loss is genetic male pattern hair loss. You seem to have the typical male pattern hair loss and It is progressive so you will continue to lose hair. If you want to make sure the cause of your hair loss is genetic, you need to see a hair loss specialist and get examined.
I suggest a formal consultation to see what is needed for you individual case. There are options. Best, Dr. Emer.
You may have noticed it two months ago, but it most certainly has been going on for some time. You might want to get a HAIRCHECK measurement of all of your hair and find out if you are losing it elsewhere. This is the best test available for detecting hair loss
You should seek a qualified dermatologist to evaluate your scalp and discuss options for your hair loss. You do not have advanced loss, just appears to be early stages of hair loss. You might discuss medical therapies with your derm but I would advise against hair transplantation in this area.