Facebook Text Messages on Cell Phone | Phone/Device Issues and Features | Consumer forum

I was alarmed when about a couple of weeks ago I got a series of text messages with strange numbers like 33333002 and 222220000 from someone saying he saw my picture on Facebook and wants to go out with me. I don't have my cell phone number listed on Facebook and I only allow friends to view my posts (whether that actually works or not I don't know). I have since cancelled my Facebook account but am perplexed at how this person got my cell phone number. Have I been hacked? Can this be done by students accessing my phone at a bus stop (I leave it by my backpack when I'm on duty to tell time and in case of emergencies)? Is Speak Out connected to Facebook and should I cancel my number/replace it with a new one? Any feedback/information would be greatly appreciated.