Help, please? I'm confused and not sure of what to do or say.....

Talk to him face to face. It's so easy to ignore a person/message on a screen but not when they are living and breathing right in front of you. Maybe he simply has not been on facebook today so he did not see your message.

Ask him in person. I cannot help with this, I'm sure he has reasons. Ask him in a nonconfrontational manner (do not use blaming or talk about reasons why he might of unfriended you, just say "I've noticed you've unfriended me on Facebook. Can you explain why?" in a calm tone). Listen carefully to what he says and try not to come to conclusions he hasn't said, then respond accordingly. I would also try checking your phone as well in case he sent a message.
Remember, facebook is just a social site. It has brought too many relationships down and broken many friendships. If you two are truly close, facebook should not bring your relationship down.

Just call him.

maybe the unfriending was an accident...I've had that happen. some1 means 2 unfriend some1 who's name just happens to b right seguinte 2 urs and they accidentally hit ur name...as 4 the rest, i rlly have no experience at all with relationships...I'm 18 n never had a bf...i sorda gave up on trying anymore...