Why am I following someone I don't know?

You follow users you send friend requests to.

You can unfollow people you are not interested in by canceling your friend requests here: vk.com/friends?section=out_requests.

If you are positively sure that you haven't sent the request, change your password in the Settings section (vk.com/settings) or here: vk.com/restore. Make sure to also scan your computer for viruses: vk.com/av.
Your search for returned no results.
Try using other keywords, e.g.: "delete profile", "create chat".
Check your request for misprints.