who is stalking me on Facebook?

A stalker can be any, if your profile is public then anyone can see your friend list, profile photo, and Details you have on your Facebook profile, and also see all the Facebook posts that you have shared in the past.
If your profile is private then only your friend can see your profile and check your details. So, make sure to make your profile private to avoid stalking. So, this is the right answer to who is stalking me on Facebook.