Me está entrando ( o picando ) el gusanillo > I have caught "the bug" or "notion" to do something.
Also " matar el gusanillo ".
Son las once de la mañana y voy a comer algo ligero para matar el gusanillo.
Its 11 am. and I am going to eat a snack to kill the hunger pangs (or notions ) before lunch.
Hope that helps.
