Happens all the time.
Sometimes it’s good to take a break – a day or two, and in that time, watch old movies that you LOVED ; things that inspired your imagination. Read books.
Enjoy the music that you listened to when you first got the bug to write. Sometimes listening to those songs bring your brain back to that special place.

But – the bottom line here is: give it time, it all comes back.

You can also read other ficlets and maybe they will inspire you!
Other ideas, write a story backwards, take a current series and bring in a new character, slow down the action and focus on one small detail, or write something really silly!