It sounds like your nut has fallen out. It is the piece of bone between the string retainer and the fretboard that positions the strings above the fretboard.
Check in your bag – or in the slot area where the neck sits in the bag. If not here, check around the last place you opened your guitar case and noticed the strings were too low on the fretboard.
To reglue the current nut, the easiest method is to remove the strings completely, then add super glue to the bottom of the nut, then position it with the flat side facing the fretboard so that the thicker slots match the thicker slots in the black string retainer. It is VERY important that you line up these slot as closely as possible so when you assemble the guitar the strings will naturally fall into these nut slots.
If you can’t find the original nut, our steel string guitars use standard 1 3/4 nut (OF422, OF310, OF660 etc..) unless they have an “N” at the end of the model number – in which case they use a 1 11/16 nut (Like PJ410N, OF312N etc..), so you can purchase one on our website or from a local guitar store. If you try to install a new nut, please note you’ll likely need to sand the bottom the nut to the proper height so that your action is not too high.
Here’s a good video on how to sand down and install a new nut on a standard guitar. https://www.youtube.com/watch?v=-_0wAb7PZ0k