You are wasting or running out of time! "Wasting" is often shortened to "wastin'." Come on, get those chores done so we can get out of here. Time's a-wastin'! Time's a-wasting, kids! You're going to fail the assignment if your experiments aren't finished by the end of the class.
Rur. Time is running out.; It is getting late. Hurry up! Time's a-wastin'! How come you're still in bed? Time's a-wastin'!