Might also be linked to your Facebook page... in which anyone that searches "find friend" on Facebook via their phone, will have your first and last name and be able to pull up your profile (if it isn't private that is)
I stumbled upon this last night while using my phone to search for an old friend from High School. What happens though is anyone in your contacts that has their number listed on their Facebook page, comes up to suggest to add them. I have seen now ladies and gents in this business who hobby/provide and now know their personal Facebook pages. Along with what is personal information.
Just an FYI... might want to either delete your number off your page, or get a different phone number for hobbying.