Blocked?

Sorry I'm frustrated and I don't know who to ask or turn to. I was talking to one of my friends like Normal and this is where I need iPhone users help. My messages to them starting turning from the blue iMessages to only green. I figured they're just out of service or their phone is turned off. But I tried calling them and the call went straight to voicemail. Then I turned off my show caller ID and the call went through and rang continuously. It shows I can still send messages as green messages. Does that mean they blocked me?