I believe it has to do with you anxiety. It's kind of the same with me. The more I sort of think about or push my self not to stutter thats when I actually stutter the most. First and foremost, just relax if it went away before. It will probably go away again. Can you think as to what may have triggered it. What were your feelings at that time and do you think they could be affecting you stutter. Once you get through that start taking steps to understanding your self and your stutter. Also weird things that have helped me: 1. Thinking before I speak not too much just a little bit don't get to caught up in your head 2. Taking a sharp inhale from the nose and then beginning to speak 3. Trying to talk in a different accent, weirdly helps sometimes also really funny. Again, I'm not a professional, this is just my opinion