Planaria tend to be slightly thicker and will show very obvious cephalization. The head will be a different shape and typically will have eye spots.
They are probably detritus worms. These won't always be from overfeeding. If you have stirred up the gravel, moved stuff, or cleaned filters recently, this can cause you to see detritus worms.
I wouldn't be worried because they aren't harmful. Plus shrimp will eat them. Oh and hi Dee haha
ďBooks are my friends, my companions. They make me laugh and cry and find meaning in life.Ē ― Christopher Paolini, Eragon
"By books you mean fish, right?" ― Raymond